KZ650 valve clearance wierdness

bluezbike wrote: Bountyhunter wrote: I have a couple of valves that will change clearance based on cam chain tension. There is up/down play of the camshafts in the journals and if I revers direction on the crankshaft nut while checking (and release cam chain tension) the clearance would change about .002" on a couple of valves.

I am a bit surprised that there is up/down play in the camshafts......I didn't think there should be any play at all, am I missing something here?

I was kind of surprised too but there is a fair amount of play.

From my FSM, it says the max allowable clearance between the cap and camshaft is 0.16mm which is about .006" if my math is correct. That means the camshafts can ride up and down a little as the lobes rotate downward and the valve spring force is pushing upwards.

typical plain bearing clearance is .0015" the .030 to .072mm spec. in the manual is about .001 to .002" Not really gonna mess up valve clearances that much. I set them to the loose side of the range given in the manual, they won't get any looser as time goes by...

Doc....., my apologies if this is a thread-jack
Thanks all......I guess the movement has to be there to allow for cams heating up and expanding when at operating temperature

I've posted before how I was taught to check clearances by a factory Kawasaki mechanic. Not a dealer mechanic, a friend of mine who worked for factory Kawasaki. Take it or leave it, but it's always worked for me.
Shims are in .05mm or .002" increments, so only need to measure using those baseline sizes, so you need a .05mm, .10mm, .15mm, .20mm feeler set.
Decide what clearance you are shooting for, usually .10 or .15mm
Lets say you are going for .10mm. Start on a valve, turn the engine over slowly clockwise with the 17mm end of your crankshaft while constantly trying to insert a .10mm feeler. If it slides in anywhere in the entire rotation of the cam, try a .15mm. If it does *not* slide in anywhere in the entire rotation, call your clearance OK at .10mm because shims only come in .05mm increments and trying to measure to .001" is fruitless and a waste of time.
If the .15mm goes in, but a .20mm doesn't, then call your clearance .15 and add 1 shim size to bring to spec most likely. Same idea, if a .05mm goes, but a .10mm doesn't then you would subtract one shim size and recheck.
The problem most run into is for whatever reason, the clearances can vary by as much as 2 sizes depending on where the cam is in it's rotation sometimes, and just checking in one place can send you in circles if you do it that way.

OK heres a theory. I didn't check the cam/cam cap clearance. Bike has alot of miles, with presumably the original head and cams. If the clearance between the cam and the cam caps is on the large end of the spectrum, if you changed the shim on say #4 and when from a 240 to a 255 when you went to measure number 3 the next rotation would #4 push up harder on the cam and because of the gap affect the clearance on #3?

Ron has the right idea, and is what I do. If it calls for a range of clearance, like 0.10 -0,20, As long as it is within that tolerance, call it good and move on to the next one. If you want to know what you have, if one goes and the next one doesn't, you know what you have for a clearance. Take the "feel" out of feeler gauges. If you are getting closer to the smallest shim available, it's time for a head rebuild.
The go, no-go valve clearance check works great.

I print out one of these every time I do a valve clearance check, because i ride my commuter 300 miles a week.
img.photobucket.com/albums/v97/CoreyClou...Pz550%20Pics/001.jpg
It is easy to make a form like this on excel, and that way you always know what shim is in there the next time you check valve clearances.

I have had times where I change shims, and the measurement stays the same, or goes the wrong way. It can happen is anything gets between the shim and bucket or valve. I change to another shim of the same size, and recheck, then it works. Patience is the key.