Question shimming?

Made the mistake when I rebuilt the engine of mixing up the shims. As a consequence I have three tight shims. Would the best way to get the right size is to remove the shim, replace the bucket (without shim) and cam? In theory the gap should measure 2.something mm. Is that correct or am I way off the mark here?

I wouldn't....the cams are not intended to make contact with the buckets on shim over bucket (i'll use abbreviated SOB, but not everyone does the same abbreviations so be warned) followers, and the shim is required to be in place on shim under bucket (SUB) followers or the bucket might push down on the retainer and not the valve stem, which could dislodge the valve keepers and drop a valve into the cylinder.

If it is SOB and you already have it assembled, then I would start making notes on which valves have clearances and which are tight, then one at a time remove the shims and record which valve and the corresponding shim thickness. Once you know what all of them are, you can play some mathematical matching games to figure out which shim goes where, a few at a time...and a bit of trial and error.

If you have SUB, then this is the best - go buy a complete set of 8 shims in the minimum thickness and install them. Cams in place for test no. 1, measure all the valve clearances and record them. Then measure all the old shims, and do the math game again until you have figured out the positions of all 8 of the old shims on paper. Then you only need to pull the cams out one more time.....re-install shims in calculated original positions and re-check clearances again...all should work out within spec.

If you don't mind buying the 8 thin shims (thank goodness it is an 8 - valve head - huh?), you could use the SUB method for the SOB to save some time and effort.....

I suggest purchasing a thin "checking shim" of known thickness, install it, measure the lash, and then calculate the proper shim size you need and order.

It's basically 3 shims which are out of spec, 2 ex and 1 in. Had the exhaust cam off this evening and the 2 tight ex shims are 2.4. Now what I did (please point me out if I've done wrong) is took out the bucket and shim on of the ex valves. Then I replaced the bucket (without shim), laid down the cam (TDC 1 - 4) there is no tension on on the cam. So I laid the ex cam and bunched some feeler gauge blades together which came to 2.20 and ran it between the bucket and cam. Now.....I'm thinking this is not precise enough so I'm thinking of buying a bunch of shims 2.40 down and trying each one. Trouble is this will prove expensive

No, if you only have 3 valves out of spec. and the other 5 are o.k.

Buy 3 thin shims and use those to check and calculate what you need....if your lucky, that is all you will need.

Like I said before, you probably shouldn't try to install a shim under style bucket follower without a shim in place...you might drop a valve into a cylinder if you inadvertently knock out a retainer collet, and that won't give you a correct clearance # anyway....

Kray-Z wrote:
Buy 3 thin shims and use those to check and calculate what you need....if your lucky, that is all you will need.

Best plan

Maybe I'm wrong, but I sense you are making a simple procedure complicated.
As Ed suggested, one thin shim is all you need. Then just move it from one bucket to another while calculating off the measurements you take.
Are you leaving the cams bolted-in while removing and replacing shims?

Your question: "In theory the gap should measure 2.something mm. Is that correct or am I way off the mark here?"
I believe so...way off, that is :blink:

The correct Kawasaki specified lash/gap measurement is between .05 and .150 mm. for my 1100 engine.

daveo wrote: Maybe I'm wrong, but I sense you are making a simple procedure complicated.
As Ed suggested, one thin shim is all you need. Then just move it from one bucket to another while calculating off the measurements you take.
Are you leaving the cams bolted-in while removing and replacing shims?

Daveo- If this is a 650, 750 or other with shims under buckets, then the cams have to come out every time for an adjustment to each / every valve...

Also, might damage the cam lobes by turning the engine without shims on top of the buckets, or dislodge a valve keeper and maybe even drop a valve into a cylinder if engine turns without a shim under a bucket, as bucket could depress just the retainer and spring...probably not going to happen, but I think anyone would regret not spending the $40-60 for extra shims if it did!

Kray-Z wrote:

daveo wrote: Maybe I'm wrong, but I sense you are making a simple procedure complicated.
As Ed suggested, one thin shim is all you need. Then just move it from one bucket to another while calculating off the measurements you take.
Are you leaving the cams bolted-in while removing and replacing shims?

Daveo- If this is a 650, 750 or other with shims under buckets, then the cams have to come out every time for an adjustment to each / every valve...

Also, might damage the cam lobes by turning the engine without shims on top of the buckets, or dislodge a valve keeper and maybe even drop a valve into a cylinder if engine turns without a shim under a bucket, as bucket could depress just the retainer and spring...probably not going to happen, but I think anyone would regret not spending the $40-60 for extra shims if it did!

Yikes, I thought the 80's bikes were shim on top, except GPZ engines. My bad. :whistle:

Shim under is the way to go with hot cams.
Steve

swest wrote: Shim under is the way to go with hot cams.
Steve

I like the :kiss: method, so the 84 GPZ cams will be it for me.
:lol:

daveo wrote:

swest wrote: Shim under is the way to go with hot cams.
Steve

I like the :kiss: method, so the 84 GPZ cams will be it for me.
:lol:

You should be using the shim under and GPz retainers and springsfor those cams! I would keep the revs below 8500, then....