Tuesday, 3 July 2018

How to check the valve clearances of a Kawasaki Z250SL

Of course this will also work for a Ninja 250SL but I don't know how the extra plastic comes off..

So, you gets your Z250SL:
And you remove the rear seat. You do this by putting the key into the lock underneath the rear seat on the left side of the bike:
And turn it until the rear seat pops up. Then pull the seat rearwards. Suddenly, it'll be off! The next step is to remove the "boomerang" bits of plastic from the rear. Yes I know you're trying to check the valve clearances but Kawasaki apparently design things arse about face so here we are playing with the fairings at the very rear of the bike.. Undo these screws:
And then unclip all the clips, maybe undo some screws on the underside if your bike still has them (mine are long gone) and pull the barbs out of their grommets at the front of this piece of ever-so-useful plastic. Suddenly, it'll be off!
The next step is to remove the rider's seat. To the rear of the most forward grommet in the above picture is a shiny silver bit with a "7" 10mm bolt in the bottom, undo the bolt and remove it all. This is a pin that holds the rider's seat in place - remove the one on the other side too. Hello gubbins!
Either side of the battery is an interesting hook thing that connects the big stupid side plastic to the stupid rear plastic:
Unhook them.

Next up is the big stupid side plastic bit thing. This is actually quite easy to remove, it is just barbs everywhere except at the very front where it is a push fit onto a rubber thing. Barbs and grommets:
Rubber hook thing on the front of the tank:
Hole for rubber hook thing at the front of the long stupid plastic thing:
I hope this makes sense? Essentially, starting from the rear of the long plastic bit of nonsense, you just pull the plastic away from the bike until you reach the front when you pull the whole plastic thing rearwards. It is easy and mercifully the plastic is bendy so you probably won't break it.

Phew! Next up is to remove the tank. Of course the 250SL is fuel injected so this isn't easy at all.. Remove the bolts from the mounts at the rear of the tank:
You now need to disconnect the power cable from the fuel pump. This is located on the underside of the tank so lift the rear of the tank upwards to squeeze your hand in. You need to squeeze this clip together and then it will let go, mine was thankfully not difficult.
Here is a picture of the connector disconnected so you can hopefully figure out which bit to squeeze to release it (hint: the left bit):
The next joyous part of this experience is to remove the "quick release" fuel hose connector from the pump. Bloody "quick release", this took me ages. This is what you're dealing with:
You will need to pull the green side parts downwards with your fingers, this is stiff and quite painful ("quick release"!). Do not just try and pull it off the pump, the manual states the pump body is made of resin and is as fragile as your Gran after a heavy night out. Here is a picture of the "quick release" removed so you can see what state it needs to be in to let go:
This will try and leak petrol everywhere so, err, be ready for it I guess? The manual says you should have disconnected the battery but ain't nobody got time fo' dat.

The next stage of removing the tank is to pull the breather hoses off the front left. This was actually really bloody awkward and difficult as Kawasaki have used those silly wire clip things to hold the hoses in place. I ended up having to keep the tank lifted up like this:
While I attacked the clips with a small screwdriver, bending them open. I did not put them back upon reassembly, the hoses are a snug fit and they're just breathers fer chrissakes.
With the tank finally cut from its tendrils simply lift the rear and slide the tank backwards - it has some prongs at the front which fit into some rubbers. I imagine these will fall to bits in time but never mind that now.

With the tank removed, place it on some wooden blocks so that no pressure is applied to the ridiculously fragile pump housing. Oh, did I not mention you needed blocks before now? I'm just going by what the manual says.. (grumble!).
The manual also says to open the tank cap so as to reduce leakage. I don't know if this works or not but I followed the advice.

So, finally, the engine is found. Undo the clip that holds the breather (?) tube on to the air box:
Now undo the two 12mm bolts and single 14mm bolt that hold that central "spine" of the frame in place, and remove it. Also pull the breather tube that you disconnected forward, underneath the top of the frame and route it somewhere out of the way like so:
It is now actually time to touch the engine! That rear seat seems like an awful long time ago..

Simply undo the four bolts that hold the rocker cover in place and remove them, this is a totally traditional design.
Once free, the rocker cover simply pulls backwards out of the space. Note that you will have to separate the rubber gasket/seal from the rocker cover as it is too thick to fit through the gap with that rubber still in place. Sadly this makes reassembly much more fiddly than it needed to be but don't blame me, blame Kawasaki.
The manual states that the spark plug cap needs to be removed but I didn't find it to be in the way at all. I also couldn't get it to budge at all so that was a good thing, in a way.

Next up is to get the rear wheel off the ground somehow. Those of you with more money than sense may have a proper stand, I prefer to use a trolley jack underneath the rear suspension arm linkage triangle thing.
Turn the rear wheel in the direction of forward travel while pulling the gear lever upwards until the bike is in 6th gear. Now keep turning/knocking the wheel in the same direction to turn the engine over - you want the inlet and exhaust cam lobes to be pointing away from each other, this is Top Dead Centre on the compression stroke. Never mind removing the timing cap and searching for TDC on there, ain't nobody got time fo' dat.
There is a good chance that the motor stopped just before TDC on the compression stroke so you probably won't have to turn the wheel very much.

With the motor in this state it is time to check the clearances. Get your feeler gauges and feel away!
The clearance specs are as follows:
Inlet: 0.10-0.19mm
Exhaust: 0.15-0.24mm

This is the same as the KLX250 so no great surprises. At around 8400 miles my clearances were:
Left inlet: ~0.15mm
Right inlet: 0.10-0.15mm
Both exhausts: 0.15-0.20mm (closer to 0.20mm)

So mine are in spec, but the right inlet is tighter than I would like which means I'll be in there again at the next service interval plus a bit because I'm lazy. Interesting fact, the owners manual states the interval for this is 7200 miles but the workshop manual says 7600 - I prefer the latter!

If any of your clearances are out of spec then please leave a comment below including the gap you found and the mileage/kilometrage of the engine. Thankfully mine were okay so installation is the reverse of removal, kind of. Be careful not to trap/crush the rubber seal under the rocker cover, and you can use some gasket goo over the cam half moon things though I never bother and have never suffered leaks. My seal played nice and went back without much bother though I did have to poke it in with a small screwdriver in one place. Otherwise, simply reassemble..
Simply push the green section of the "quick release" connector back into place, mine took a bit of wiggling and then suddenly snapped in, and slather some grease/petroleum jelly on the barbs on the plastics, maybe some more in the rubbers that hold the front of the tank, and job's a good 'un. Phew!


  1. Dammit Snod! You beat me to it. Mucho Grassy Ass, this will help me a lot when I do Sharon's.

  2. Snod - just done Sharon's tappets at 15,600 miles.
    Inlet 0.10 and 0.13. Within but on the low side
    Exhaust 0.13 and 0.15. So one was just a leeeeetle too tight.

    All 4 adjusted to wider end of the spec.

    CAN I...use one of your images in my blog? I haven't got one of the removable metal bit from the frame above the rocker cover.

    1. Of course you can, my man! Interesting that the valves seem to be tightening, I've got a way to go yet (only at 11K) but I'll post my experiences.

      I look forward to the write up, hope there aren't any big gotchas with adjusting the clearances.

  3. Valves tighten not loosen - generally - especially bucket and shim. The cam to bucket interface it pretty tough and well lubricated. However the valve to valve seat interface when new has a lot of rough edges. the first few valve checks where the seats and valves bed in cause "recession" into the head and the tappets to close.

  4. Too bad they were in spec, otherwise i'd now know how to go about getting them back in spec aswell, ha! Oh well, should be same procedure as klx250, thanks for the write up! Enjoyed the read, agree on all counts of stupid plastic...

    1. Z250SL news hot off the press, Ren has had to change the clearances! Check out his guide:


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