valve shim clearance

I have a 1978 kz650d sr and would like to know what my valves clearance should be or a range, also can it be done without taking the cams off.If my gap is too much will the bike not idle well.

Post edited by: drotti2004, at: 2006/08/11 00:05

welcome to kzr
i believe the 650 has under bucket shims that require the cams be removed i dont know the clearance range but you might find that in the filebase section

you are right the 650 is a under bucket shim, and you do have to remove the cams, watch the timing chain,
I would get a manuel prior to starting any work on the bike

I believe the correct clearance is .015. We have claerance Clarence.

I doubt your valve clearances are "too much" as you put it. Clearance between cam lobes and buckets/shims decrease with wear. Can this cause idle problems? Possibly but probably not. I suspect, based on your questions, your bike might be due for a full tune up which I would recommend before going farther to resolve the idle issue. Valve clearances, cam chain, ignition timing and replacment of tune up parts THEN carburetors. See my web site for a description of valve clearance work on a 900/1000. On that model, the shims that space the buckets from the lobes are on top the buckets. The cams stay in to check and adjust clearances. On YOUR bike, the clearances can and should be checked with the cams in place but clearances adjusted (changing shims) is done by removing the cams as the shims are UNDER the buckets meaning the buckets (and thus the cams) must come out to change shims to adjust clearances, if needed.

The specified clearance is .15mm which is 6 thousanth of an inch. Basically if you can insert a .10mm feeler and not insert a .20mm feeler anywhere throughout the rotation of the cam, you are in spec. Guys make it harder and much more complex than need be by lining up timing marks, using goofy size feelers ect. Just use feelers in .5mm increments only and slowly rotate the engine clockwise as you try to insert the feeler to check clearances. If clearance needs adjusting on a KZ650 the cam needs to be removed. Do this one cam at a time, keeping chain tought as it goes down in the engine as you carefully move the cam towards the center of the engine to gain access to the buckets. This way the timing is not altered and no resetting of the chain timing will be needed.

I meant to say use feelers only in .05mm increments, .05mm, .10mm, .15mm, .20mm ect.