ZZR250 Valve clearance --- Cheap solution

[stevew_zzr]

Can anyone tell me the specs for the valve clearances on a ZZR250 (1992)? I haven't even popped the cam cover off yet so I have no idea what kind of cam arrangement it's got (my guess is two cams, one to operate intake and one to operate exhaust valves) and the valves are directly actuated by the cam lobe? Are they adjustable, or shimmed or ... ???

Cheers!

p.s. Can someone dang well upload the ZZR250 manual ? I had a look at the GPX250 manual but how would i know if they are the same or not, after all I'm an idiot!

[mike-s]

the engines on the two are identical, so what suits one, suits the other

[krusty]

Clearances are;
Inlet: 0.08 ~ 0.13mm
Exhaust: 0.11 ~ 0.16mm

The ZZR250 supplement refers to the GPZ250R base manual for the procedure.

[Tones]

They are adjustable btw.

Cheers

[stevew_zzr]

So i gather it has to be done with the engine warm then

If it's the same set-up as in the GPX250 manual then it should be easy enough (not painful, as per my car having damn shim-over buckets which have to be replaced or machined in order to adjust the valve lash).

Thanks for those number krusty

[bonester]

Nope valve clearances are measured cold.

[stevew_zzr]

Well sadly this is not going well... the valve clearance is 0.003 of an inch on the exhaust side, which is probably WAY too small to get any decent film of oil between the cam lobe and the rocker (and explains a bit about why my engine is so noisy) only problem I have, is how the hell do I adjust them? Usually you can just fit an open-end spanner or something over the lock-nut, but it looks like my goose is cooked in that regard (really badly designed head if ya ask me).

Does ANYONE have the service tool or some way of undoing the lock-nuts on the rocker arm ? I REALLY need this desperately as I won't be going to Mallala tomorra unless i can get these adjusted and sorted tonight!

Thanks anyone who can help.

[bonester]

Have you timed the engine correctly? At TDC etc? I think both pistons on the ZZR go up and down together- you really need a service manual to time the engine right to measure the valve clearances. That clearance you mention sounds way too small- I would check that you are measuring correctly first.....

[krusty]

I think both pistons on the ZZR go up and down together

Urban myth, they oppose each other.

I'm contacting the site admin so I can upload the ZZR supp & I'll scan a few pages from the GPZ250R base manual to help you.

EDIT: the ZZR250 manual and the valve clearance part of the base manual is on the server and waiting to be transfered to the public folder

[stevew_zzr]

Have you timed the engine correctly? At TDC etc? I think both pistons on the ZZR go up and down together- you really need a service manual to time the engine right to measure the valve clearances. That clearance you mention sounds way too small- I would check that you are measuring correctly first.....

clearance does vary a bit but it's never more than .006 - which is definitely *way* too small. Possibly someone has adjusted it incorrectly before and the rocker has worn to that clearance, or alternatively maybe the valve seat or the valve head has worn down. Who knows...

Either way i can't do crap all about it at the moment

[ZZRCHIKKY]

the hole point of having more than one cylinder/piston is so that on e is at the point of exsplosion wile the other is compressing or what eva so that u dont have any dead point . . . so what would the point in having 2 cylinders that are at the same place all the time ???


that is one hell of a DUH moment !!!

[Tones]

Steve,

Here is some pics of the tools I use to do the job. We are in Vic, otherwise would come and help. The tube socket is a 10mm with flats cut into each side so a 10mm spanner can grip the top, whilst the screwdriver is used to adjust the clearances. Make sure you re-check after you have nipped up the lock screw. Tis a pain in the arse job. There is a "workshop" tool to do the job which essentially looks the same except the spanner is welded to the tube socket. Hope this helps.

[Gosling1]

. . . so what would the point in having 2 cylinders that are at the same place all the time ???

a 360deg twin as you describe, does not *necessarily* have to fire both pistons at the same time.........they are *generally* fired 180deg of 'crank' rotation apart...

It is easier to balance a 360deg twin with 1 balance shaft, than a 180 deg twin that fires every 360deg of crank rotation........there is an effect called a 'rocking couple', and it is not something you see in Penthouse

We could spend a lifetime discussing this..........there are *heaps* of 360deg twins out there......and plenty of 180deg twins as well....

[stevew_zzr]

I'll have to try and find a 10mm deep socket around that I can afford to butcher a bit, and that will fit onto the exhast tappet clearance adjuster without fouling on the damn head (i did try a deep socket with a screwdriver in it but it was a bit too fat to fit).

Yeah i originally thought that the ZZR motor would be a 360 degree twin simply because it's a hell of a lot easire to balance the crank, so i was suprised when it turned out to be a '180' twin.

[krusty]

the hole point of having more than one cylinder/piston is so that on e is at the point of exsplosion wile the other is compressing or what eva so that u dont have any dead point . . . so what would the point in having 2 cylinders that are at the same place all the time ???


that is one hell of a DUH moment !!!

Big bang engines exist, where some or all cylinders fire at once. The Ducati motogp engine is a V4 that fires as a V2. read a bit of this too http://www.motorcycledaily.com/08april05_bigbang.htm

Kawasaki have some tools you can buy that make your life easy and they are not too expensive and pay for them selves when you use them once.