The International CBX Owners Association

Anyone have, just sitting around collecting dust, a set of 6 ea (270) valve shims I can use to begin the gapping process on my newly fitted valves? Hate to have to buy a set that I in all likelihood will not end up using.

Leslie:
If you put every shim/bucket back where it came from, you won't be too far off. Do yourself a favor and pick each shim out and measure it before you install the buckets - saves a bunch of work removing each after the cams are installed. Then just measure the clearances you end up with and you can select the appropriate shim to replace those needing it without removing them again just to check shim size. And you'll have a record of every shim in the engine.

Dave

Hi Dave, I'm afraid that if I use to thick of a shim, or whatever shim was there already, I might do some damage when clamping down the cam caps and finding out that there was interfierence from the get go. Does that make any sense? Preston, the man that reffited the valves suggested I start with a thin shim and work my way from there. I'm doing all the shimming on my benchtop and will re-check them again when on the bike.

Leslie:
I'd still do what I said, for the reasons I said. But you'll need a lot of dummy shims if you do it the other way. Unless Preston cut the seats a lot, you'll be close.

Dave

Even if a shim is too big, it should not hurt anything, to assemble as long as you don't start the engine. It will just hold a valve partially open. You will find that too-large shim when you check clearances and correct that.

Gentlemen, Preston out of Orlando Fl, graciously offered to send me the shims I need to finish the project. Thanks for everybody's input, but special thanks to Preston. What a great community! I will post end results in a previous thread I started.

I am a little confused about what the concern is. The only thing that could have happened is that Preston would have cut the new seats too far into the head and that using a thick shim, the valve would stick open. That is an unlikely scenario.
As the valve stem is still the same length and the cams still have the same lift, you can really start with any size shim in any of the positions and measure the gap and re-shim according to the specifications.

You are right my friend. That is exactly what I did. All seems to be good now. Thanks for the input.