Fitting K75 Showa forks to an 8v K100

There is an unspeakable truth about the Sachs/Brembo forks that come on the 8v K100s - they're really badly made. They have no steel bushes and instead have the stanchion (chromed bit) slide directly inside the leg/slider (bulky aluminium bit). I've even seen it said on K100 forums that this is good because it means the weight of the leg is less.. What nonsense! Anyway, the upshot is that the aluminium of the leg starts to gall and this munches great big scores into the stanchion and then you have a leaky fork - mine were leaky when I bought it and I've seen a few over the years that also have leaky forks, most owners insisting that they just need new oil seals which of course won't help the fact that the two bits don't fit together very well any more. There was even a guy on the old gbbikers forum (SAS Tom if he ever reads this!) who bought new stanchions in the hope it would stop his forks leaking.. Of course they didn't, he just wasted his money. Eventually I got tired of having a saggy, springy front end with forks that would just puke out any oil I put in and something had to be done. A front end swap to the 16v set up with Marzocchi cartridge forks (that kinda work) and proper brakes was incredibly tempting but also very difficult due to the current ABS system and throttle cables not being a straight swap. Instead I decided to fit some Showa forks off a late K75 (and the Mystic R850, I think) which don't come up for sale very often but if you're patient you'll get some eventually - I paid £106.60 after a few months of waiting. The Showas are a very basic damper rod design but in their favour they hold oil and are almost a straight swap save that the stanchions are 41mm diameter instead of the Sachs/Brembo's 41.3mm. No one on the K100 forum could say for definite if the old yokes would clamp the new forks but I gave it a go anyway. So..

Crappy Brembo forks. These are identifiable from the rib that runs down the legs and from the oil that covers the travelling section of the stanchion..

The later K100s and K75s have a fork brace that BMW said wouldn't be necessary because of the oversized front axle (K fun fact) and this means they also use a two piece mudguard, one piece either side of the brace. They are connected by a long bolt that fits a square nut in the front half. This gets sprayed with literally ALL the muck and salt and water and promptly corrodes into place, another fantastic design decision. Bring on a tool of destruction.

A worn down cutting circle fitted in the gaps and only chopped the mudguard and brace a little bit before doing its job:

I'll worry about that later, for now I have some exciting new forks to fit! Old ones on the right, new ones on the left.

Ahh Showa! And smooth stanchions!

And a pic of the Brembo codes, in case it's any help to anyone?

Right, slap them in!

It is true, they are indeed a straight swap - the calipers bolt right up, the original axle fits and after a whole lot of persuasion the yokes will clamp the forks in place.. Just about. I had to tighten the bolts 3 or 4 times to stop the forks working their way up past the yokes but did get there in the end. I still plan to fit some late K75 yokes for peace of mind though.

With that done and the concept proven it was time to get back to that blasted mudguard. My first attempt was to use some mole grips (a real professional's tool, I think you'll agree) to squeeze a nut onto the square nut in the mudguard to stop it spinning and then turn the remains of the bolt out.

This didn't work.

After literally seconds of thinking I decided that there was only one way to go, it may be destructive but the mudguard is no good as it is. Where's my soldering iron and plastic welding tip..

The slot actually works quite well and it gave me an opportunity to close up the hole underneath that both lets all the muck get to the nut but also allows the washer to fall out when I'm putting it back together. I hate this mudguard so much.

With that little fun problem solved I could finish the job..

..And go for a test ride!

First impressions were that I was riding uphill everywhere, as I was so used to the super saggy forks that were on there before. The Showas barely sag when the bike is taken off the stand and sag only slightly more when I sit on it, personally I prefer more sag than that but I guess it's better than it was.

Second impressions were that the ride is very harsh and crashy, obviously this is to be expected with damper rod forks but I didn't expect it to be quite so hard. However it is a definite improvement over the old forks and damper rod forks can always be modified with less/thinner oil or even cartridge emulators so I'll probably end up doing that one day. But for now it's nice to have forks with damping!

Z250SL rear brake pad change

Nothing too interesting here but again as the owner of probably the most rotten Z250SL ever I feel I should report that I found the rear pads were losing their friction material at 18809 miles! I was innocently replacing the rear tyre (again) and poked the pads to see if they were going to make it through an MOT. Then I saw the gap, and, well..

Humph. Now where did I put those super dooper excellent pads that I bought a while ago.. Ah yes!

I've had some success with Chinese pads in the past, of particular note were the non-name ones I put in the CB250 which were actually excellent if a bit short lived. These were £4.83 a pair on ebay which is reasonable even by my standards.

Eventually the pins were persuaded out of the rear caliper (what a horrible design!) and the true extent of the carnage was revealed:

This bike is yet to see its first MOT. I find the 3 year period absolutely ridiculous because of stuff like this. Anyway, I also couldn't help but notice my brand new AKAs were rusting already..

Oh well, they're still going in. There seems a good amount of copper in the pad material too, always is in these cheapo pads.

Extra pictures of the rotten one for science:

So, basically, if you run a 250SL (or probably any Thai-made Kawasaki) through a salty winter then be sure to check your brake pads aren't falling to bits. AKA pad review coming soon!

Z250SL muffler replacement

As the owner of what is surely the most abused and neglected Z250SL in the British Isles I feel I should report about the stonkingly poor build quality of the exhaust. Here is how it looked not long after I bought it:

And here is how it looked after 18574 miles and another crash:

It had been noisy for at least a couple of months previous to this but the crash really finished it off. The noise was tiresome and the bike's first MOT was drawing near so I figured I had to fix it. What I really wanted was an Ixil can but these require real money to be spent so instead I bought a very-slightly-used original exhaust from ebay for £36.01, I can only thank the vain person who thought it was wise to fit something aftermarket. So, remove the bolt from the passenger footpeg hanger and remove the muffler..

I had to giggle.

In the interest of science I tried to get some pictures of inside the can but my phone insisted on focusing on the grass instead, when will technology allow us to manually operate the focus??

Not a lot to it really, why are they so expensive? It was also well on its way to rotting in other places too:

The next step was to get what was left of the muffler section off the stainless downpipe. I like that at least some of the exhaust is stainless but why not make it all stainless?? Anyway, it is held on with a clamp which I thought was going to be a nightmare to get off - not so! I hammered a socket on to what was left of the bolt head, gave it a good twist and the whole clamp tore off! Result.

Happily the new exhaust came with its clamp so this was no loss at all. Also if this is supposed to happen by design then it's brilliant.

So, twist and heave on the remains until it comes off.

It wasn't too difficult to remove, and the remains of the gasket were quite easily removed with a wire brush. I did consider fitting a new gasket but the one left in the new exhaust still looked fine (it wasn't torn up) and have you seen the price of them?? So on it went.

Upon starting it sounded very much like a sewing machine, only slightly less embarrassing but much less offensive. Overall a good job but a shame I had to do it so soon. Also the footpeg hanger is bent after the crashes which means the bolt hole isn't quite where it should be any more, I did consider bending it back but if it snaps off then I'm in deep doo-dah so I left it. An insurance person would probably write it off because the frame is bent, oh well..

Super professional crash fixes

Back on the 4th of July this year (it was raining and I still had to wear my heated gloves!) I chucked the Z250SL up the road on its right side after locking the front on some patches of road that were worn smooth and polling the rain water. It was only at about 15MPH or so but the usual damage was done - bent handlebars and a bent brake lever. This also finished off the exhaust but that was already well rotten so never mind. So, here is a guide on how to enact super mega professional back street mechanic type fixes to your freshly rashed machine!

Step 1 - Bend the bars back to where they were with a big bar.

The lock stops and top clamps can take it, they bent the bars in the first place anyway. This is actually really easy if you have a bar long enough, I used some aluminium scaffolding pipe which was brilliant for this job. Result:

I went a little too far the other way but I'm sure the next crash will sort that out for me. Next problem - bent brake lever:

For this job you will need the hallowed pump pliers on scrunchiness..

Scrunch, twist, grab, bend..

There, good as new. Sadly the exhaust is more difficult to fix, so I set up an ebay search - that'll be a separate post!