Changing Cams and Valve Clearances

Hey gang - I am swapping the hotter Gpz 750 cams into my 650 head. The Kz750 exhaust cam tach drive gear decided to disintegrate last week and now is as good a time as any to put in the hotter Gpz cams which I picked up from kawasakiman (thanks Steve.)

DKMK (Dave) and I were just speaking on the phone and we were both curious as to what I might expect as far as any valve clearance issues or changes I may encounter.

The Gpz 750 cams have higher lift and more duration than the Kz750 cams. My clearances were just checked a couple of weeks ago and came in from 0.08 - 0.15 mm.

I have Gpz750 intake valves (trimmed 15 thous) and stronger springs in the ported and milled 650 head. I only had 10 thous taken off the head to clean up the mating surface.

So, with these newer cams, will I be looking at putting in thicker shims to keep the clearances within spec?

Cheers-Colin Firth-Ontario Canada

Post edited by: reborn650, at: 2007/05/04 12:41

it will be the base circle of the new cams that you are installing, the only way to find out is to put the smallest shim in and figure out how much of a shim you will need, but I wouldnt think that there would be too much a change though

BSKZ650 wrote:

it will be the base circle of the new cams that you are installing, the only way to find out is to put the smallest shim in and figure out how much of a shim you will need, but I wouldnt think that there would be too much a change though

Correct. Milling the head has nothing to do with valve lash clearances.

Jay

APE Jay wrote:

BSKZ650 wrote:

it will be the base circle of the new cams that you are installing, the only way to find out is to put the smallest shim in and figure out how much of a shim you will need, but I wouldnt think that there would be too much a change though

Correct. Milling the head has nothing to do with valve lash clearances.

Jay

Jay - I just opened the package from Z1Enterprises with the APE manual cam chain adjuster I bought. What a beautiful machined piece of artwork that is. I should've got one last year and saved myself a lot of hassles and repairs.

So, guys, even with the new higher lift cam I should be pretty close with the current valve clearance which are all in the 0.08-0.15 mm range, is that correct?????

Cheers-Colin Firth-Ontario Canada

Glad you liked it.

Your clearance adjustment will only be as close as the base circle diameter of the two cams.

Jay