Way back in January I was given this flyer for an easter egg run that happens not only in the fair shire of Leicester but also happens to be just a couple of villages over from where I live. My interest was piqued.
Sure enough, March rolled around and surprisingly the forecast was looking good so after popping down to an enormous B&M that exists in Coalville to arm myself with a Peppa Pig easter egg I rolled into the car park in Anstey, unsure of what I would find. Unsure partly because I've never done an Easter egg run before (though I can guess what is involved!) but also partly unsure because I'm not at all religious - will I even be welcome?
With the weather as glorious as it was and safe in the knowledge that all group rides are dog slow I puttered to the top of the hill on the glorious CBX250RS and parked up amongst a surprisingly large number of bikes considering I've been riding for the past 9 years and never heard of this going on.
As I remove my helmet, gloves and earplugs a bloke quickly walks over to check what on Earth can make such a wonderful noise, and then nips off again without saying anything. Weird but I shouldn't expect anything less, at least they seem to like what I've brought!
I hand the 'Pig egg over to a bloke who puts it in the back of a hearse (???) with the rest of the donations and the Christians begin their preaching and thanking. Mercifully it is short and sweet and soon everyone is readying themselves for the run:
There was some interesting machinery here, as there always is for group rides, though sadly the bicycle moped thing was nowhere to be seen after this point.
Upon leaving the car park we were waved off by people holding small wooden crosses, again a bit much but I mustn't hold it against them - for some reason I wouldn't mind nearly as much if I was on some Diwali ride and they gave people Tilaka marks.
And so we set off towards Cropston, I think touching Rothley and then following a route quite similar to the Brass Monkey run to end up at, surprise surprise, The Vic in Coalville. Sure enough the pace was sedate and the CBX was more than capable enough despite not breathing properly. I don't mind though, it's part of the fun once you know the score and accept it.
So, overall this is a nice little jaunt with good planning and perfectly lovely people and I think it could be a great event if they sort their marketing out so people actually know it is on - perhaps this post will help them! There is a niche to be filled here, I don't know of any other Easter egg runs in the Leicester area or even in the East Midlands and the ones over in Birmingham or Wirral seem very popular. Come on guys, get the word out!
Showing posts with label CBX250RS #1. Show all posts
Showing posts with label CBX250RS #1. Show all posts
Monday, 21 May 2018
Sunday, 24 May 2015
CBX250RS-E Engine Rebuild 16/04/2013
I have replaced the cams and rockers with ones with hardly any scarring from CBX #2 (details of which will come later..) and it now runs almost as quietly as it once did, albeit a bit tappy. I could tighten the clearances a bit more, but I'm still not convinced it's quite right - although I'll happily run it in now. However I have come across something that may help shed some light on the mystery.. While stripping the ruined engine for it's piston (for #2) I had a good look at the connecting rod and saw that the rod from SEP does indeed have an extra hole:
I remember wondering about it at the time but I didn't have anything else to compare it to, since I didn't have other cranks to look at or the old rod. But I wonder if oil can escape more easily from the crank then perhaps this accounts for the seemingly lower oil pressure? Do replacement rods often have new holes in? I don't really know what to make of it.
As an aside the old crank seems fine, no play on the rod up or down, so it must have only been a main bearing. Ah well!
I remember wondering about it at the time but I didn't have anything else to compare it to, since I didn't have other cranks to look at or the old rod. But I wonder if oil can escape more easily from the crank then perhaps this accounts for the seemingly lower oil pressure? Do replacement rods often have new holes in? I don't really know what to make of it.
As an aside the old crank seems fine, no play on the rod up or down, so it must have only been a main bearing. Ah well!
CBX250RS-E Engine Rebuild 04/04/2013
An update! Now that the weather has warmed almost to tolerable levels (at least for the past few days) I have continued to put it all back together. I won't bore you with that again, but today was finally test ride day. I thought that the clockwork knocking noise had gone away, at least a bit, but after getting the motor hot it was back just the same as it had been before I had new valves fitted - so it wasn't the valves making the noise! It seems to run just fine though so screw it for now. Since I now have a spangly smartphone I recorded a clip of the noise (and proof that it runs!), any ideas are hugely welcome.
The noise seems to be mostly from the left exhaust area, which incidentally is furthest away from the oil feed into the rocker cover. The feeds are clear though and plenty of oil is making it to the top, so short of sticking in a tiny camera to see what's going on I cannot verify if it's getting enough oil or not. I also wonder if maybe the exposed bits of metal under the hardened layer on the cams/rockers have corroded a little and are now catching slightly. I am clutching at straws though. Whatever it is it doesn't seem to affect how the bike runs, and if it is just cam/rocker related then it's no big deal to fix later on if I do find out what it is.
The noise seems to be mostly from the left exhaust area, which incidentally is furthest away from the oil feed into the rocker cover. The feeds are clear though and plenty of oil is making it to the top, so short of sticking in a tiny camera to see what's going on I cannot verify if it's getting enough oil or not. I also wonder if maybe the exposed bits of metal under the hardened layer on the cams/rockers have corroded a little and are now catching slightly. I am clutching at straws though. Whatever it is it doesn't seem to affect how the bike runs, and if it is just cam/rocker related then it's no big deal to fix later on if I do find out what it is.
CBX250RS-E Engine Rebuild 30/01/2013
My, how time flies. Some time last year I stripped it back down and took the head off and had it sitting around for a bit. Then I bought 4 new valves, two inlets from Econohonda in New Zealand and two exhausts from David Silver. I then took it all to a place called Coventry Boring and Metalling and asked them to fit the new valves and get them to seal - they said they would grind them in as needed. They also refused my offer of a workshop manual, so imagine my surprise when I got the head back and found they had reassembled it with half the valve springs upside down, apparently unaware that they are progressive. I had paid £33.60 for the privilege, too. I then took it (along with another head for another CBX250 I seem to have acquired which needed a valve seat) to Zoom Factory which is a bloke in a room, who cut the seats properly and charged me £60 for the privilege, but at least he knew what he was doing. Long story short, I hopefully have a working head and I am unemployed once more so have the time to do it. Oh hello, you!
One lovely looking head, hopefully sans knocking:
And after a bit of work..
The bolts holding the head down are supposed to be torqued to 50Nm, I got to 40 and went a bit more before wussing out. I think it'll be alright though. The carbs are also currently refusing to go back into their rubbers, even with the help of a rubber mallet - I think this must be down to how cold it is, I have a heatgun if things get desperate. I can't believe how long it's been though, crazy!
2 x inlet valves - £52.63
2 x Exhaust valves - £36
1 x Head gasket (again!) - £14.94
Zoom Factory head work: £60
Running total: 1147.49
One lovely looking head, hopefully sans knocking:
And after a bit of work..
The bolts holding the head down are supposed to be torqued to 50Nm, I got to 40 and went a bit more before wussing out. I think it'll be alright though. The carbs are also currently refusing to go back into their rubbers, even with the help of a rubber mallet - I think this must be down to how cold it is, I have a heatgun if things get desperate. I can't believe how long it's been though, crazy!
2 x inlet valves - £52.63
2 x Exhaust valves - £36
1 x Head gasket (again!) - £14.94
Zoom Factory head work: £60
Running total: 1147.49
CBX250RS-E Engine Rebuild 15/04/2012
Another weekend, another update..
Yesterday I took the bike out of the garage where noise can reverberate and gave it a little run outside. Upon closer inspection it appears that the noise is actually coming from the top, so I quickly stripped it back down and replaced the cam holder that hadn't wanted to torque down properly just in case the cam was leaping around underneath it. The new holder and it's bolts torqued down properly, but when it went back together it sounded just the same! The only thing left was tappets, so today I set them properly with care and attention. I didn't expect it to make any difference as to my mind the sound is too heavy to just be tappets, but I put it together yet again and whaddya know, it was quiet! For about a minute anyway. It's now back to being noisy but at least I know what it is, all I have to do is get those cams to fit. I guess it is possible that I have mismatched a cam lobe and it's rocker but I am fairly sure they are all back in their original places.. It didn't used to be noisy with this valvegear at all though so I don't understand why it sounds like clockwork now.
Anyway, here is the new oil pipe that runs up the outside of the engine and feeds the rocker cover, which squirts oil at the cams:
I figured it was worth paying £7.20 to be sure this pipe was clear. I also took a photo as proof that the thing does actually work, even though I have built it..
So there you go.. This bike broke almost 2 years ago with a terminal knocking sound, and it has now been repaired to the point where it only has a nasty sounding slap at the top end. I shall have to get the new cams to fit somehow, and then it's all good! Particular thanks to guru for his help taking the stupid thing apart, and qwakers for help on putting the stupid thing back together, it was always appreciated. Now to sort out a way to change gear, and get the wheels respoked, and sort out the cams, and get it MOT'd, and whatever else needs doing..
1 x oil pipe (11335-KE5-010) - £7.20
1 x new rocker cover gasket/seal - £5
Running total: 983.92 still including unused top end bits..
Yesterday I took the bike out of the garage where noise can reverberate and gave it a little run outside. Upon closer inspection it appears that the noise is actually coming from the top, so I quickly stripped it back down and replaced the cam holder that hadn't wanted to torque down properly just in case the cam was leaping around underneath it. The new holder and it's bolts torqued down properly, but when it went back together it sounded just the same! The only thing left was tappets, so today I set them properly with care and attention. I didn't expect it to make any difference as to my mind the sound is too heavy to just be tappets, but I put it together yet again and whaddya know, it was quiet! For about a minute anyway. It's now back to being noisy but at least I know what it is, all I have to do is get those cams to fit. I guess it is possible that I have mismatched a cam lobe and it's rocker but I am fairly sure they are all back in their original places.. It didn't used to be noisy with this valvegear at all though so I don't understand why it sounds like clockwork now.
Anyway, here is the new oil pipe that runs up the outside of the engine and feeds the rocker cover, which squirts oil at the cams:
I figured it was worth paying £7.20 to be sure this pipe was clear. I also took a photo as proof that the thing does actually work, even though I have built it..
So there you go.. This bike broke almost 2 years ago with a terminal knocking sound, and it has now been repaired to the point where it only has a nasty sounding slap at the top end. I shall have to get the new cams to fit somehow, and then it's all good! Particular thanks to guru for his help taking the stupid thing apart, and qwakers for help on putting the stupid thing back together, it was always appreciated. Now to sort out a way to change gear, and get the wheels respoked, and sort out the cams, and get it MOT'd, and whatever else needs doing..
1 x oil pipe (11335-KE5-010) - £7.20
1 x new rocker cover gasket/seal - £5
Running total: 983.92 still including unused top end bits..
CBX250RS-E Engine Rebuild 09/04/2012
And so, upon further inspection, the new cams are different to the old
ones. The old ones are larger in diameter by 1mm and the bearings that
are on them have a diameter 1mm smaller.. The new cams with their larger
bearings were never going to fit. This is quite a downer, and I can't
understand how this would be the case when the new cams are a superceded
part, but they're just not going to fit without major work.
I shall refit the old rockers and cams for now and figure something out at a later date, at least it'll run for a bit.. It's not going to be how I'd like it though :(
The old cams have bearings with a 20mm inner and 37mm outer diameter, making them a normal 6904 bearing. The newer cams have bearings with a 19mm inner and 38mm outer diameter, which is not a standard size but can be found. I did have a quick look for bearings with a 19mm inner and 37mm outer but I can't find any, though maybe they exist somewhere.. I do wonder if they could be got from Honda as a sort of conversion kit? It is quite possible they are imperial, but I don't have anything precise enough to measure tenths of a millimetre. The bearings themselves have SC0481C3 written on them if that helps, and of course they are from NTN (or at least I think they are).
The past few days have been very busy, with the old stuff fitted back on it was time for all the other stuff to be put on - carbs, airbox, wiring, all faffed about with. I did have an issue with one of the bolts for a cam holder not torquing down properly but it seems to hold it okay. In fitting the rocker cover I came across an odd problem - the manual clearly states that the spring for the small bit of tensioner should go around the bolt, but if it were there the gasket for the cover couldn't fit..
I just curled the spring around the casting instead, it certainly looks more like where it should go. I also fitted a brand new oil pipe to feed the top end, filled the engine with oil from the head so everything at the top was sitting in a pool, and feverishly plumbed it all in. at around half nine tonight the tank was on and it was time to go.. It turned over about 6 times and gave a pop. A couple more churns and it came to life! I was happy for about 3 seconds until I noticed the odd, off beat knocking of metal on metal.. It's almost like a large version of gear chatter. My Dad reckons it's the cam chain, I reckon it's something to do with the primary drive or the clutch. More revs make it louder and more often though, whatever it is. Otherwise it runs fine, no smoke or death rattles, but this knocking is something of a let down. It doesn't even seem to leak oil!
I'll take the clutch cover back off and look for shiny bits, but I really don't know what it might be :(
I shall refit the old rockers and cams for now and figure something out at a later date, at least it'll run for a bit.. It's not going to be how I'd like it though :(
The old cams have bearings with a 20mm inner and 37mm outer diameter, making them a normal 6904 bearing. The newer cams have bearings with a 19mm inner and 38mm outer diameter, which is not a standard size but can be found. I did have a quick look for bearings with a 19mm inner and 37mm outer but I can't find any, though maybe they exist somewhere.. I do wonder if they could be got from Honda as a sort of conversion kit? It is quite possible they are imperial, but I don't have anything precise enough to measure tenths of a millimetre. The bearings themselves have SC0481C3 written on them if that helps, and of course they are from NTN (or at least I think they are).
The past few days have been very busy, with the old stuff fitted back on it was time for all the other stuff to be put on - carbs, airbox, wiring, all faffed about with. I did have an issue with one of the bolts for a cam holder not torquing down properly but it seems to hold it okay. In fitting the rocker cover I came across an odd problem - the manual clearly states that the spring for the small bit of tensioner should go around the bolt, but if it were there the gasket for the cover couldn't fit..
I just curled the spring around the casting instead, it certainly looks more like where it should go. I also fitted a brand new oil pipe to feed the top end, filled the engine with oil from the head so everything at the top was sitting in a pool, and feverishly plumbed it all in. at around half nine tonight the tank was on and it was time to go.. It turned over about 6 times and gave a pop. A couple more churns and it came to life! I was happy for about 3 seconds until I noticed the odd, off beat knocking of metal on metal.. It's almost like a large version of gear chatter. My Dad reckons it's the cam chain, I reckon it's something to do with the primary drive or the clutch. More revs make it louder and more often though, whatever it is. Otherwise it runs fine, no smoke or death rattles, but this knocking is something of a let down. It doesn't even seem to leak oil!
I'll take the clutch cover back off and look for shiny bits, but I really don't know what it might be :(
CBX250RS-E Engine Rebuild 06/04/2012
With the tensioner in place the next step was to fit the idle gear that sits in the middle and drives the two cams. With the flywheel having the "T" position at the inspection point this gear should have two lines on it showing level with the top of the head.. This took about 5 goes to get right the first time, and a couple more the second time with the tensioner properly in place. The tensioner also has to be let off by sticking something in the hole on top of it and levering it the wrong way so that the tension is taken off the chain, leaving just enough slack to get it into place. Quite a game getting it all lined up, but finally it was done..
The next step was to torque up the stuff on the bottom. All the big bits (clutch centre nut, primary drive and the flywheel bolt) were somewhat straightforward although I used a tool meant for undoing oil filters on cars to hold the flywheel in place while I did it up. The manual reckons it should be torqued to 100-120Nm which is twice as tight as the head! We got to 90Nm, then with the torque wrench set to 100Nm the filter tool snapped.. I reckon it's good enough though. I also had a problem with these 10mm bolts that hold the clutch release mechanism in place:
The manual doesn't give a torque figure for these but the usual is about 12Nm. They torqued up to 10Nm just fine, but come 12Nm one stretched and then snapped! I took the bolts out of the other engine and fitted those instead, again 10Nm was fine but with the wrench set to 12 two of them started to stretch.. I gave up there. Maybe I should buy some new ones?
Next up was the cams! They have a spring loaded sub gear on the outside to stop chatter and this had to be taken off and fitted to the new cams I have bought.. Another game laid in wait.
Taking a pair of circlip pliers to the old ones they exploded in a shower of springs and washers, I knew it was going to be fun straight away!
The manual says to simply press the springs into the troughs (or whatever you want to call them) and fit the sub gear over the top. As if! Of course the springs would ping out with nary a care in the world, in the end I put them half in and put the sub gear on top, and then twisted and pushed it into place, occasionally poking the odd misbehaving spring back into its hole. Eventually this was done, and with a bolt holding the sub gear in the same position as the cam gear (thanks to s screwdriver in the teeth and someone else tightening the bolt..) it was time to fit the new cams! Timing it up is easy, simply line up the marks..
Oddly Honda seem to have gotten the intake and exhaust sides mixed up on these markings, my other cams are the same. Save for some snapped bolts in the clutch which were easily extracted it was all going well, right until I tried to fit the cam holders. The bearings on the cams simply do not want to fit their cut outs in the head, there is a rather large gap underneath them:
I tried simply tightening the holders down, and one snapped in half! I won't be trying that again in a hurry, but it leaves me wondering what to do. Can I simply heat the head enough to let the bearings drop in? Is there a special technique for this that the manual isn't telling me about? I'm stumped!
1 x inlet camshaft (14110-KE5-010) - £70.80
1 x exhaust camshaft (14120-KE5-020) - £70.80
Running total: £971.72
The next step was to torque up the stuff on the bottom. All the big bits (clutch centre nut, primary drive and the flywheel bolt) were somewhat straightforward although I used a tool meant for undoing oil filters on cars to hold the flywheel in place while I did it up. The manual reckons it should be torqued to 100-120Nm which is twice as tight as the head! We got to 90Nm, then with the torque wrench set to 100Nm the filter tool snapped.. I reckon it's good enough though. I also had a problem with these 10mm bolts that hold the clutch release mechanism in place:
The manual doesn't give a torque figure for these but the usual is about 12Nm. They torqued up to 10Nm just fine, but come 12Nm one stretched and then snapped! I took the bolts out of the other engine and fitted those instead, again 10Nm was fine but with the wrench set to 12 two of them started to stretch.. I gave up there. Maybe I should buy some new ones?
Next up was the cams! They have a spring loaded sub gear on the outside to stop chatter and this had to be taken off and fitted to the new cams I have bought.. Another game laid in wait.
Taking a pair of circlip pliers to the old ones they exploded in a shower of springs and washers, I knew it was going to be fun straight away!
The manual says to simply press the springs into the troughs (or whatever you want to call them) and fit the sub gear over the top. As if! Of course the springs would ping out with nary a care in the world, in the end I put them half in and put the sub gear on top, and then twisted and pushed it into place, occasionally poking the odd misbehaving spring back into its hole. Eventually this was done, and with a bolt holding the sub gear in the same position as the cam gear (thanks to s screwdriver in the teeth and someone else tightening the bolt..) it was time to fit the new cams! Timing it up is easy, simply line up the marks..
Oddly Honda seem to have gotten the intake and exhaust sides mixed up on these markings, my other cams are the same. Save for some snapped bolts in the clutch which were easily extracted it was all going well, right until I tried to fit the cam holders. The bearings on the cams simply do not want to fit their cut outs in the head, there is a rather large gap underneath them:
I tried simply tightening the holders down, and one snapped in half! I won't be trying that again in a hurry, but it leaves me wondering what to do. Can I simply heat the head enough to let the bearings drop in? Is there a special technique for this that the manual isn't telling me about? I'm stumped!
1 x inlet camshaft (14110-KE5-010) - £70.80
1 x exhaust camshaft (14120-KE5-020) - £70.80
Running total: £971.72
CBX250RS-E Engine Rebuild 01/04/2012
Time to update this before I get too far ahead and find I'm too lazy to write it all up..
The first step was to sort out the suraface of the head to try and make it clean for a good seal around the bore. A scraper just wasn't managing it so I took some 400 grit sandpaper to it, and it cleaned up really quite nicely:
The next step was to set the new head up with some rockers that aren't scored, these are the originals:
I actually consider these to be pretty good, they're in better condition than the other set and the inlets actually look good enough to be usable spares. This is a nice backup as I have the last two new inlet rockers anywhere in the world as far as I can tell. With the new rockers installed with the old tappets in place it was time for a final scrape of the barrel, fitting a head gasket and torquing the head down! I gave the large bolts a thorough wire brushing (the more wire brushing the better, it seems), coated them in oil and set myself up with a torque wrench expecting a stripped thread.. But it went smoothly! The threads seem to be in much better shape than the ones holding the barrel to the cases, but maybe I just didn't brush those bolts enough? Anyway, the head was on with smooth and shiny new rockers to boot:
Oddly the Honda workshop manual that I am using says that there should be wave washers between the rockers and the bits of head that hold them in place, but neither engine has had any. There is no play side to side either, so I can only guess Honda changed the design at the last minute. There isn't even any room for a washer of any sort.
The next step was to fit the not-yet-understood cam chain tensioner, something I had not been looking forward to. At first it plopped into place but wasn't tensioning very much, but some reading ( http://www.xrv.org.uk/forums/xr/39982-tutorial-fitting-xr600-cam-chain-tensioner.html ) showed me the error of my ways. I still didn't really know where the spring went but I tried my best, some mole grips and a cable tie producing this:
After a bit of a fight it fell into place, and as it happens the bit of the spring that sticks out goes under the pin that holds the tensioner in place. Here it is plopped in:
And, after a bit more of a fight, the pin was in too:
The cable tie was then cut off by using a small set of wire clippers and the use of mole grips. Brutal, but effective. Suddenly the chain guide was shoved into the way and everything was a lot more awkward, so it was probably right!
That is all I have pictures of so far.. More has been done, but this would be no fun without the pics.
1 x head gasket (12251-KG0-004) - £12 (already added in to the running total because I got confused earlier!)
2 x inlet rockers (14431-KL8-710) - £78 (roughly due to exchange rates from the Netherlands and New Zealand)
2 x exhaust rockers (14441-KE5-003) - £81.60 (from the Netherlands)
Running total: £830.12
And none of this includes postage either..
The first step was to sort out the suraface of the head to try and make it clean for a good seal around the bore. A scraper just wasn't managing it so I took some 400 grit sandpaper to it, and it cleaned up really quite nicely:
The next step was to set the new head up with some rockers that aren't scored, these are the originals:
I actually consider these to be pretty good, they're in better condition than the other set and the inlets actually look good enough to be usable spares. This is a nice backup as I have the last two new inlet rockers anywhere in the world as far as I can tell. With the new rockers installed with the old tappets in place it was time for a final scrape of the barrel, fitting a head gasket and torquing the head down! I gave the large bolts a thorough wire brushing (the more wire brushing the better, it seems), coated them in oil and set myself up with a torque wrench expecting a stripped thread.. But it went smoothly! The threads seem to be in much better shape than the ones holding the barrel to the cases, but maybe I just didn't brush those bolts enough? Anyway, the head was on with smooth and shiny new rockers to boot:
Oddly the Honda workshop manual that I am using says that there should be wave washers between the rockers and the bits of head that hold them in place, but neither engine has had any. There is no play side to side either, so I can only guess Honda changed the design at the last minute. There isn't even any room for a washer of any sort.
The next step was to fit the not-yet-understood cam chain tensioner, something I had not been looking forward to. At first it plopped into place but wasn't tensioning very much, but some reading ( http://www.xrv.org.uk/forums/xr/39982-tutorial-fitting-xr600-cam-chain-tensioner.html ) showed me the error of my ways. I still didn't really know where the spring went but I tried my best, some mole grips and a cable tie producing this:
After a bit of a fight it fell into place, and as it happens the bit of the spring that sticks out goes under the pin that holds the tensioner in place. Here it is plopped in:
And, after a bit more of a fight, the pin was in too:
The cable tie was then cut off by using a small set of wire clippers and the use of mole grips. Brutal, but effective. Suddenly the chain guide was shoved into the way and everything was a lot more awkward, so it was probably right!
That is all I have pictures of so far.. More has been done, but this would be no fun without the pics.
1 x head gasket (12251-KG0-004) - £12 (already added in to the running total because I got confused earlier!)
2 x inlet rockers (14431-KL8-710) - £78 (roughly due to exchange rates from the Netherlands and New Zealand)
2 x exhaust rockers (14441-KE5-003) - £81.60 (from the Netherlands)
Running total: £830.12
And none of this includes postage either..
CBX250RS-E Engine Rebuild 30/03/2012
Cor valves are difficult!
I attempted to some make sort of impression on the carbon that is welded to the valves with a coin but all I ended up with was a valve with a bit of coin added to it in orange streaks. My Dad saw me trying this and took a valve off me, and then proceeded to put it in his lathe and attack it with the tip of a flathead screwdriver! The graunching noises were unbearable to my mind but the valves appeared to have come through the experience unscathed, and missing all of the deposits to boot! Filled with confidence the next task was to fit the new stem seals (four 12208-413-003P, £18.96 total), which was relatively easy in the grand scheme of things although the old ones put up a bit of a fight. They simply pop on and off the top of the guide which is a bit like a barb, I was quite pleased with the progress.
Then came putting the valves back together with their springs. What a nightmare! If I ever want new springs fitting to anything again I'm getting a workshop to do it! Getting the collets or cotters or whatever you want to call them to fit back in where they should proved an impossible task by the normal route, they simply wouldn't stick in the groove that they're supposed to occupy at the top of the valve stem. Instead we (poor dad gets roped into more than he should) had to compress the springs and the valve cap quite a way down, get the collets to sit in the gap between the stem and the cap and then slowly undo the spring compressor tool to let the cap and collets slide up the stem and hopefully have it all locate into place. This was a tricky business with much frustration and use of dentistry tools, but eventually we had one done:
And then, with the experience we had gathered, the rest followed a bit more quickly..
This all took at least two hours of poking, prodding, compressing and undoing. If only my paranoia of breaking valve springs wasn't so strong! Anyway, so we now have four inner springs (14761-KE5-003, £9.60) and four outer springs (14751-KE5-003, £12) fitted and ready to go. I'll also show you how much cleaner the valves are now:
They are that clean on the back, too. I didn't bother to touch the valve seats as I have used this head and the compression seemed just fine, and frankly I have no idea at all what I am doing if I start grinding away at stuff.
I am somewhat concerned by the rust that can be seen in the top right of that picture though, it is from the previous head gasket and whilst being fairly smooth now it is still not as good as the rest. Could it affect compression if I don't clean it up to a mirror shine? I don't really want to take sandpaper to it as it'll end up being uneven, surely? And I don't really want to get it skimmed because the compression ratio is already 10.5:1 so there's not much metal to spare..
I attempted to some make sort of impression on the carbon that is welded to the valves with a coin but all I ended up with was a valve with a bit of coin added to it in orange streaks. My Dad saw me trying this and took a valve off me, and then proceeded to put it in his lathe and attack it with the tip of a flathead screwdriver! The graunching noises were unbearable to my mind but the valves appeared to have come through the experience unscathed, and missing all of the deposits to boot! Filled with confidence the next task was to fit the new stem seals (four 12208-413-003P, £18.96 total), which was relatively easy in the grand scheme of things although the old ones put up a bit of a fight. They simply pop on and off the top of the guide which is a bit like a barb, I was quite pleased with the progress.
Then came putting the valves back together with their springs. What a nightmare! If I ever want new springs fitting to anything again I'm getting a workshop to do it! Getting the collets or cotters or whatever you want to call them to fit back in where they should proved an impossible task by the normal route, they simply wouldn't stick in the groove that they're supposed to occupy at the top of the valve stem. Instead we (poor dad gets roped into more than he should) had to compress the springs and the valve cap quite a way down, get the collets to sit in the gap between the stem and the cap and then slowly undo the spring compressor tool to let the cap and collets slide up the stem and hopefully have it all locate into place. This was a tricky business with much frustration and use of dentistry tools, but eventually we had one done:
And then, with the experience we had gathered, the rest followed a bit more quickly..
This all took at least two hours of poking, prodding, compressing and undoing. If only my paranoia of breaking valve springs wasn't so strong! Anyway, so we now have four inner springs (14761-KE5-003, £9.60) and four outer springs (14751-KE5-003, £12) fitted and ready to go. I'll also show you how much cleaner the valves are now:
They are that clean on the back, too. I didn't bother to touch the valve seats as I have used this head and the compression seemed just fine, and frankly I have no idea at all what I am doing if I start grinding away at stuff.
I am somewhat concerned by the rust that can be seen in the top right of that picture though, it is from the previous head gasket and whilst being fairly smooth now it is still not as good as the rest. Could it affect compression if I don't clean it up to a mirror shine? I don't really want to take sandpaper to it as it'll end up being uneven, surely? And I don't really want to get it skimmed because the compression ratio is already 10.5:1 so there's not much metal to spare..
CBX250RS-E Engine Rebuild 11/03/2012
After stewing over it for a bit and looking at the prices of having a head repaired (!) I did some looking on t'interweb and it appears that cracks between the plug and valves are something of a feature of RFVC engines, particularly the 250s and particularly the earlier dual carb models as they have less space between the plug and valves than later variations. In fact people were recommending getting another head with cracks that are nowhere near as bad as mine, like this - http://www.thumpertalk.com/topic/681904-84-xl-600/.Mine is also the only example I can find with a crack on the inlet side, basically it's scrap and then some. So I begrudgingly started stripping down engine number 2 expecting to find it will be just the same, but no! Something actually worked out well!
That'll do nicely!
I'm not sure how it has survived so well, I ran it with smaller jets and an air leak in the airbox for a thousand miles and I wasn't kind to it, and I have a suspicion it has been raced. But it doesn't matter.. Onwards!
That'll do nicely!
I'm not sure how it has survived so well, I ran it with smaller jets and an air leak in the airbox for a thousand miles and I wasn't kind to it, and I have a suspicion it has been raced. But it doesn't matter.. Onwards!
CBX250RS-E Engine Rebuild 10/03/2012
Ah more warmth! Today was barrel day, I was not looking forward to it but it has to be done! First I covered the bore with oil, then the piston rings and then the top edges of the piston, not sure if that was necessary but I had lots of oil to hand. The manual says to then put some liquid gasket on the "meting areaes" where the cases come together around the conrod, then slap the base gasket on (12191-KG0-306, £5). Then put the crank at bottom dead centre and simply squeeze the rings together while sliding the barrel over the top. Even the picture of the bloke doing it in the manual looks like he's having trouble but the two of us (me and my dad) managed it without much drama. I hated torquing it down to 50Nm though, the bolts clicking away like the thread was already stripping. Anyway, the end result was this!
More progress! I then decided to clean the old gasket residue off the head, and when I was about halfway I noticed something that looks bad. Like, horrible at this stage of the game. As in, well..
Both of the cracks are on the left side, I guess this is a result of the dual carb setup even though there is some odd reed valve stuff going on inside the head to try and equal it out. The left side is the primary carb so it gets used more than the right side, and the use of smaller main jets in the past by some idiot has taken its toll. So is this still usable or am I to strip the head off the other engine? I was really hoping this build would last for at least 30K before needing attention, I guess that is out of the question with damage like this? It makes me sad :(
Oil pipe from previous post: £10
Base gasket: £5
Running total: £629.96
More progress! I then decided to clean the old gasket residue off the head, and when I was about halfway I noticed something that looks bad. Like, horrible at this stage of the game. As in, well..
Both of the cracks are on the left side, I guess this is a result of the dual carb setup even though there is some odd reed valve stuff going on inside the head to try and equal it out. The left side is the primary carb so it gets used more than the right side, and the use of smaller main jets in the past by some idiot has taken its toll. So is this still usable or am I to strip the head off the other engine? I was really hoping this build would last for at least 30K before needing attention, I guess that is out of the question with damage like this? It makes me sad :(
Oil pipe from previous post: £10
Base gasket: £5
Running total: £629.96
CBX250RS-E Engine Rebuild 03/03/2012
So today I stripped it down some more..
And then a bit less!
Now that the new engine is held in the frame it was time to attack the seal on the output shaft that I had knocked in too far. I went with the method a fellow on gbbikers suggested and put a couple of screws in it. To say that this method worked a treat would be an overstatement, but after drilling some small holes in the seal and finding some screws that would actually bite it could finally be levered out, a screwdriver on the head of one screw levered against the head of the other. It's not a job I would want to do again, but it's done:
Almost feels like progress!
And then a bit less!
Now that the new engine is held in the frame it was time to attack the seal on the output shaft that I had knocked in too far. I went with the method a fellow on gbbikers suggested and put a couple of screws in it. To say that this method worked a treat would be an overstatement, but after drilling some small holes in the seal and finding some screws that would actually bite it could finally be levered out, a screwdriver on the head of one screw levered against the head of the other. It's not a job I would want to do again, but it's done:
Almost feels like progress!
CBX250RS-E Engine Rebuild 25/02/2012
While I was wishing the weather would warm up so I can start working on the bike outside I had plenty of time to look at what I had done. There was one part in particular that didn't seem right to me - the pipe that goes from the oil pump to the gearbox. It just didn't seem to fit right at the gearbox end and I couldn't imagine it would get any pressure behind it without just blowing oil all over the place. I got so annoyed by it that I did some research and found that Silvers had a couple of these pipes (part number 15510-KF0-010) in stock for a mere tenner, the peace of mind of having a pipe that fitted and was known to be clear was well worth it. They are actually quite different at the end:
The new and superceding pipe being on the right. It fits much better now so I'm a lot happier..
Next up is get the old engine out! The first step is to strip it down some while basking in sunshine that is actually warm:
And that was as far as I got today. I am torn on whether to install the piston and barrel in the house or to do it in the garage, the thought of coating everything in oil indoors seems bad but the thought of fiddling about with the little C clip things that hold the gudgeon pin in place out in the garage seems ripe for mishaps as well, those little blighters can't wait to get away.
Oh yeah, and I took a closer look at the gear change linkage. Little wonder it wear so quickly, the force is pushing in a very strange direction - why didn't honda just lengthen the arm on the shaft so that it was all straight??
Baffling..
The new and superceding pipe being on the right. It fits much better now so I'm a lot happier..
Next up is get the old engine out! The first step is to strip it down some while basking in sunshine that is actually warm:
And that was as far as I got today. I am torn on whether to install the piston and barrel in the house or to do it in the garage, the thought of coating everything in oil indoors seems bad but the thought of fiddling about with the little C clip things that hold the gudgeon pin in place out in the garage seems ripe for mishaps as well, those little blighters can't wait to get away.
Oh yeah, and I took a closer look at the gear change linkage. Little wonder it wear so quickly, the force is pushing in a very strange direction - why didn't honda just lengthen the arm on the shaft so that it was all straight??
Baffling..
CBX250RS-E Engine Rebuild 02/02/2012
With my lovely (cheap) new low range torque wrench to hand it was time to torque some bolts! First, of course, were the bolts holding the cases together, then the bolt holding the cam chain tensioner "arm" thing with some thread lock on it for some reason, then fit a bunch of cogs to the crank in the right order WITHOUT that strange large blue washer - I have since found that lives under the alternator. The manual says to line the cogs up with a cut out on the crank which doesn't exist, instead one of the teeth has a notch in it and I think that's what Honda used instead. After that was rebuild the oil pump (super easy) as the drive gear had of course fallen out, although the screws holding the pump together are only done up as tight as I could manage while holding it in my hand as the manual has nothing to say on torque values for those screws.. Anyway, bolt the stuff on and it looks like this:
It was all quite satisfying and easy, even the circlips holding on the gears for the shaft that lets the starter motor drive the flywheel didn't put up much of a fight. I also fitted a new cam chain (£25 off ebay) and some oil seals which go around the output and the gear shift shafts on the outside. The seal for the gear shift shaft refuses to fit properly, insisting on being wonky, but hopefully it won't let oil past:
I also pushed the seal for the output shaft as far as it could go, but now I think about it maybe that was stupid as it could be rubbing on the bearing inside. The two seals were £7.50 from Wemoto, not exactly as the originals seals were but they seem about right. The only thing bothering me is where that output shaft seal should actually be..
Price of bits in this post: £32.50
Running total: £614.96
It was all quite satisfying and easy, even the circlips holding on the gears for the shaft that lets the starter motor drive the flywheel didn't put up much of a fight. I also fitted a new cam chain (£25 off ebay) and some oil seals which go around the output and the gear shift shafts on the outside. The seal for the gear shift shaft refuses to fit properly, insisting on being wonky, but hopefully it won't let oil past:
I also pushed the seal for the output shaft as far as it could go, but now I think about it maybe that was stupid as it could be rubbing on the bearing inside. The two seals were £7.50 from Wemoto, not exactly as the originals seals were but they seem about right. The only thing bothering me is where that output shaft seal should actually be..
Price of bits in this post: £32.50
Running total: £614.96
CBX250RS-E Engine Rebuild 26/01/2012
Yesterday I went to see Mr Dave East in Enderby, what a helpful chap he is. Whilst talking to me and explaining that the case is designed to just have the bearing shoved in as it has a steel band around where the mains go, he nonchalantly knocked it the rest of the way in with a soft hammer, I would guess it was leather. Why didn't any of you guys suggest that, I felt like a right dunce! This left me with such a beautiful sight..
The next step was then to put the cases together. Eek! The first time I did this the gear change shaft didn't seem to have any effect on the shift drum, so I took them apart again and removed the shifty-shaft and claw, looked at it, wondered why it wouldn't work, turned the drum a little and put it all back. Somehow it then worked! So I took it apart again, broke into my bottom end gasket set meant for the GB250 (part number 061B1-KL8-000) which was £20 off ebay, fitted the gasket between the two halves, put it together and it all still worked. I seem to have all 6 gears up and down the box, it seems springy and notchy and generally good. I then broke out the new bolts from David Silvers and after some trial and error got them in what appears to be the right places, leaving me with this:
I put the bolts in dry, without any copper grease, as that is what the manual states but it doesn't seem right to me. I understand the bolts are coated in that strange black lacquer that I would guess is supposed to stop them seizing but it doesn't seem to work that well!
Oh and to keep up the tally of costs, the shift shaft/claw thing was £92.40 including VAT, and the order with all the bolts came to £145.73. This means the total cost so far is £582.46 and there's a lot more to come yet..
The next step was then to put the cases together. Eek! The first time I did this the gear change shaft didn't seem to have any effect on the shift drum, so I took them apart again and removed the shifty-shaft and claw, looked at it, wondered why it wouldn't work, turned the drum a little and put it all back. Somehow it then worked! So I took it apart again, broke into my bottom end gasket set meant for the GB250 (part number 061B1-KL8-000) which was £20 off ebay, fitted the gasket between the two halves, put it together and it all still worked. I seem to have all 6 gears up and down the box, it seems springy and notchy and generally good. I then broke out the new bolts from David Silvers and after some trial and error got them in what appears to be the right places, leaving me with this:
I put the bolts in dry, without any copper grease, as that is what the manual states but it doesn't seem right to me. I understand the bolts are coated in that strange black lacquer that I would guess is supposed to stop them seizing but it doesn't seem to work that well!
Oh and to keep up the tally of costs, the shift shaft/claw thing was £92.40 including VAT, and the order with all the bolts came to £145.73. This means the total cost so far is £582.46 and there's a lot more to come yet..
CBX250RS-E Engine Rebuild 21/01/2012
Today some interesting bits arrived, the most interesting of which was a 24610-KF0-010 or a gear change shaft, mine for a measly £77:
Fitting all the circlips and springs to it from the old one was surprisingly easy and things were going well until I found my Dad had messed with the case with all the gearbox in it and shifted it all out of place, so I had to fit the damn selector forks, their shaft and the shift drum together yet again. It's still not any easier, but I've now hidden it from him so hopefully that's the last time I have to do that little job. With it all together I have something that looks pretty good..
So good in fact I wanted to put the cases together and see if I have any gears! The only thing in my way was fitting the other main bearing into the right hand case, but it couldn't be too bad, the other slotted straight in with the help from a heat gun right? Nooo..
It's wedged tight, the burn marks are bits of my gloves that couldn't take the heat. Now I have to waste even more time and find someone with a press to get it the rest of the way in, oh how I laughed.
Fitting all the circlips and springs to it from the old one was surprisingly easy and things were going well until I found my Dad had messed with the case with all the gearbox in it and shifted it all out of place, so I had to fit the damn selector forks, their shaft and the shift drum together yet again. It's still not any easier, but I've now hidden it from him so hopefully that's the last time I have to do that little job. With it all together I have something that looks pretty good..
So good in fact I wanted to put the cases together and see if I have any gears! The only thing in my way was fitting the other main bearing into the right hand case, but it couldn't be too bad, the other slotted straight in with the help from a heat gun right? Nooo..
It's wedged tight, the burn marks are bits of my gloves that couldn't take the heat. Now I have to waste even more time and find someone with a press to get it the rest of the way in, oh how I laughed.
CBX250RS-E Engine Rebuild 16/12/2011
I also managed to fit the shift drum in place yesterday, this was also quite a game. I found it was best to put the drum in first, then place the forks in the right place and line them up with a channel in the drum, and then shove the rod the forks slide on through the 3 holes (on the end of the forks). It was all super awkward but it's done, and I have no idea how you're supposed to put it all back in the cases as drum, forks and shaft as one. You simply don't have enough hands!
Today I ordered a bunch of "special" bolts, a gear change shaft and a head gasket from Silvers. It may take 3 weeks to arrive as they have to source a lot of bits from various places and they close down for Christmas, so I guess that stops play for a bit. A bit of gear change linkage is also on it's way to me from SCB Motorcycles near Edinburgh for a tenner, seemed reasonable enough to take a punt on! Especially as the CBF250 it's from had done less than 8K miles.
Oh yeah and I almost forgot, of course I have spent more than £347.73 so far as the cost to get all of the stuck bolt removed was £65, and I needed a special clutch locking tool at £18 and a special bolt to act as a flywheel puller which was £6, so the total is actually a ridiculous £436.73! Bear in mind having a decent GB250 engine sent over from Japan was looking to cost £500-550 but people said it wasn't worth it, shows what they know!
Today I ordered a bunch of "special" bolts, a gear change shaft and a head gasket from Silvers. It may take 3 weeks to arrive as they have to source a lot of bits from various places and they close down for Christmas, so I guess that stops play for a bit. A bit of gear change linkage is also on it's way to me from SCB Motorcycles near Edinburgh for a tenner, seemed reasonable enough to take a punt on! Especially as the CBF250 it's from had done less than 8K miles.
Oh yeah and I almost forgot, of course I have spent more than £347.73 so far as the cost to get all of the stuck bolt removed was £65, and I needed a special clutch locking tool at £18 and a special bolt to act as a flywheel puller which was £6, so the total is actually a ridiculous £436.73! Bear in mind having a decent GB250 engine sent over from Japan was looking to cost £500-550 but people said it wasn't worth it, shows what they know!
CBX250RS-E Engine Rebuild 15/12/2011
On Tuesday me and my Dad went to a place called Charnwood Restorations which mostly deals with fixing Royal Enfields - who better to have a look at the main bearings of a single cylinder engine eh? The very helpful mechanic said that lateral play (side to side) is not a big deal and it's only radial play (uppy downy) that I should be worried about, and basically the bearings were new and perfectly fine. I still don't like them, I find the wobbliness of it all to be terrible for new parts but with such a weird size (32x76x17.5mm) I have no choice and must use the correct Honda part 91001-KE5-018. Oh well, onwards and upwards! Today the house was empty so I laid down some newspaper and snuck it inside.. This is what I have:
Yes the connecting rod is now bright orange, no I don't know why. You can also see that SEP dutifully fitted the new rubber mounts and apparently didn't charge me for the pleasure, although they DID clean the gasket off the cases and charge me for that - I was never asked if I wanted this service, in fact it was never mentioned, but I'll go along with it as cleaning gasket off is a right 'mare. I've also decided to keep a record of just how large a money pit this turns out to be, to give others an idea of how much such a project will cost. The bill from SEP was £277.73 for a new "Big End" and rod kit, supplying a couple of new main bearings and cleaning the cases. The four rubber mounts cost almost exactly £70 including VAT but not delivery from CMSNL, so we're already up to £347.73 before we even start!
Anyway, first off is the gearbox. Happily this all seems fine and I kept it all together so it was simply a matter of slotting it all back together. This took quite a lot of faffing and head scratching but I finally ended up with this:
It looks a lot like it did when it came out, and all the slidey bits seem to slide like they should! It only took about 45 minutes to get to that stage..
A couple of things about this picture. For a start, the bobble on the star at the end of the drum operates the neutral light which I find a neat solution but it's little wonder they can't be trusted. But secondly is the state of the splines on the gear change shaft - a new shaft is at least £80 if I can get one at all. I could always weld it all together again like it used to be but the linkage also isn't in great condition with a large amount of play on its rose joint. The same item looks very similar on the newer CBF250 though..?
The other problem I have is bolts - the originals are mostly well on their way to being rounded, but the size of the flange is different to that of the "normal" M6 hex bolts with 8mm heads. A quote from Silvers suggests a price of around £70 just for new bolts! Oh what to do..
Yes the connecting rod is now bright orange, no I don't know why. You can also see that SEP dutifully fitted the new rubber mounts and apparently didn't charge me for the pleasure, although they DID clean the gasket off the cases and charge me for that - I was never asked if I wanted this service, in fact it was never mentioned, but I'll go along with it as cleaning gasket off is a right 'mare. I've also decided to keep a record of just how large a money pit this turns out to be, to give others an idea of how much such a project will cost. The bill from SEP was £277.73 for a new "Big End" and rod kit, supplying a couple of new main bearings and cleaning the cases. The four rubber mounts cost almost exactly £70 including VAT but not delivery from CMSNL, so we're already up to £347.73 before we even start!
Anyway, first off is the gearbox. Happily this all seems fine and I kept it all together so it was simply a matter of slotting it all back together. This took quite a lot of faffing and head scratching but I finally ended up with this:
It looks a lot like it did when it came out, and all the slidey bits seem to slide like they should! It only took about 45 minutes to get to that stage..
A couple of things about this picture. For a start, the bobble on the star at the end of the drum operates the neutral light which I find a neat solution but it's little wonder they can't be trusted. But secondly is the state of the splines on the gear change shaft - a new shaft is at least £80 if I can get one at all. I could always weld it all together again like it used to be but the linkage also isn't in great condition with a large amount of play on its rose joint. The same item looks very similar on the newer CBF250 though..?
The other problem I have is bolts - the originals are mostly well on their way to being rounded, but the size of the flange is different to that of the "normal" M6 hex bolts with 8mm heads. A quote from Silvers suggests a price of around £70 just for new bolts! Oh what to do..
Subscribe to:
Posts (Atom)

















































