Project Bought a ZXR250C.

Well I ordered the bars...

Still waiting on the clutch basket to arrive. I forgot to get exhaust gaskets and new rubbers for the cam cover bolts, got all that now, just waiting on the basket as I want to do that job first.

I'm itching to see if it solves the shitty idle / rattle and low rpm jerkiness.

My second suspicion is partially blocked idle jets making the idle lumpy.

Could need another valve check/adjustment, I have done at least 12,000km since I last did it.

 

Tadaaa! It finally arrived.



Flipped it over and had a look, whadda ya know, springs and rivets. Which means that the old basket can be repaired. With the way my current one is behaving, I'm betting that both the springs and rivets have had it. Bike nearly has 70,000km on it if the odometer is to be believed.



Bad news: Have to work tomorrow, but I did tell them I would like to do this job tomorrow. Hopefully I can get it done.

 

Clutch baskets have differences between them so I was not able to fit the new one today

The old one has a needle roller bearing and a solid bushing that you remove before you can get the basket out of the engine. The new one has a pressed in bushing. I pressed the bushing out of the new basket, but the inner diameters are different by half a millimetre, so the needle roller was sloppy. No go.





On closer inspection, the back gear teeth are slightly different in sizing as well. So either I have the wrong clutch basket, or possibly the design was updated somewhere. The bike is a C6 (Malaysian), I ordered a C7 basket... but my engine is out of something earlier, a C1 or C2 as it is 45HP.



At least I was able to get in behind the basket and change the springs out. Shifts are a lot firmer now.



A peek at #4 conrod




Looks like I will be spending the evening finding out what parts I need to make this new basket work.

Could drill them both and swap the back section onto the new basket & springs, and then re-rivet the thing together. Old basket is worn but not terrible, could not find any slop in the riveted section... some of the springs were iffy though.

 

Have done some thinking & comparisons with the parts diagrams on megazip.

The back gear being different can be worked around. It is for the oil pump, so kind of important. The part numbers are exactly the same, no "/A" revisions or anything, but I still don't trust it. New model gear will be ordered along with circlip and pin.

That just leaves the spacer on the (input/output?) shaft and the bushings etc which are still cheaper than another basket.

However it means I lose the needle roller bearing. I would prefer to keep that set up as in my opinion it's going to last a lot longer than a press fit bush in the basket (that you can't buy separately) and solid bushing

Opinions?

 

It looks like they changed the basket from 13095-1194 to 13095-1249 starting with the ZX250-C4, as they don't list the older part # or have the needle roller bearing in the diagram from that model onward.

I did not realise they listed the superceded part and the new one on the same diagram for the older C model variants, I went straight to the C7 and ordered the basket based off that.

The oil pump gear part # has not been superceded at any point on the C models, so I wonder why the teeth are different on the new basket... it is also exactly the same across all the ZR250 variants... maybe mine is just worn?

In any case, parts cannon loaded

 

Handlebars came in yesterday, got them fitted after work, rode home, made some more minor adjustments and they are pretty much how I want them.



Wanted to mount them this way and higher up, but not enough space, didn't clear the top triple clamp



Fitted.





They are out maybe 1/2" more and at a more neutral angle. Going to see if I can raise them a bit higher. Trouble is getting the clutch perch and brake lever to clear the instruments and switchblocks clearing the nose fairing.

Had to grind the pin off the throttle side switchblock as a temporary measure, will drill the handlebar and fit a new pin as soon as I can.

The stock right handlebar has bent a little bit up near the clamp for the fork





My priority now is recovering and lowering / flattening the profile of the rider's seat. I have half a day off tomorrow, might venture down to clark rubber...

 

After retrieving the baffle from in the exhaust and replacing the bolt, it has come loose and disappeared again. Not hiding down in the exhaust, must be out on the side of the road somewhere

Got something set aside from work, in the way of an akrapovic shorty off a BMW S1000RR, a bit scratched up, but just so happens that the diameter is the same as the ZXR header flange... just waiting on the OK from the big boss.

I've got two other mufflers that need modifying but should fit, the one from Omar @XCite Bikes and a screaming demon one from @kiffsta

Hopefully should get those sorted soon.

 

That's had the last bit of the flange cut off and some bits cut out of the inside by the looks of it.

Mine looks like this with the exhaust off - see the end past the bolt holes

 

Good news! I got the rest of my clutch basket bits in and fitted, except for the oil pump drive gear (no clearance to remove the gear), today. It was a f#$%&ing headache though... after refitting the sleeve to the new clutch basket, the solid bushing was playing silly buggers, but it went in OK. Then the clutch hub bound up tight against the basket.

So it all got pulled off and checked again. Nothing wrong, all measurements OK. Refit again, tadaa it works. Even got the hub torqued to spec, not just zapped with a big rattle gun.

Bad news - bike still rattles. I'm going to have to re-do the balance. I now know for certain that it is the oil pump gear rattling against the clutch basket. I also know that I must still have an air leak somewhere on #4 cylinder, as during the previous balance job, the bike ran perfectly smooth with all pots except #4 synced. That will be my next saturday job.

Next set of tyres I am going to do all of the wheel bearings and seals plus cush drive.

Some clutch pics

 

Played with the balance again today. Couldn't get the motor to stop rattling, tried ignoring the vacuum sync and just playing with the screws but it achieved nothing. Gave up on that.

Re-balanced the carbs, adjusted the mixture screws, fiddled with it until it was happy.



Road tested it, smoothest it has ever run. Pulls cleanly from low RPM and the new clutch is amazing.

Still at square one on the rattle.