Valve shims touching

[thebottle]

All the valve shims on the exhaust cam do not have any clearance right now. They have around 280 shims in now, I swapped in a 240 which was the smallest that I had and they were still touching. I'm going to try 200 and hope for a clearance, but if not, what are my options? Do I have to have the valve length ground down?

[DiverRay]

How long since the engine has run? If it's been sitting for a while, the valves could be "stuck", and the clearance could end up being off. Try running the engine for at least 10 minutes, let it cool, and then measure the valves again.
IF it has been running, then yes, you will need to pull the head so you can grind a little of the valve stems.

[thebottle]

Alright, thanks, the engine was ran last fall, could they still be stuck? I have the engine out because I had the jug bored for a big bore kit, and I had the head shaved, and valves reseated with new seals... I was just putting it back together and checking the clearances and noticed it. Probably because the valves were ground and the head was shaved they ended up being too long. Strange that the intake valves are still in spec though, but I'm going to try a 200 shim and hope it works. If not, I'll pop the head back off and shorten the valves.

[crazy steve]

Sorry, but you can't shorten the valves any meaningful amount. There's a minimum specified length needed or the shim will ride on the bucket rather than the end of the valve. This will cause the valve retainers to loosen/tighten at each cycle and they'll fail, dropping a valve into a cylinder. You have three possible choice if smaller shims don't get you the right clearance; one, try to find new exhaust valves (and if the seats have been ground too much, this won't help), two, find somebody with a surface grinder and have some shims cut even thinner, and three, get another good head and start over. Actually grinding the valves/seats on these has resulted in this before, most owners simply lap the existing valves, removing as little material as possible.

[thebottle]

Damn, I really hope the 200 shims give me what I need then, I'm going to try and find one today to check it.

[skids]

Check a different make for the shims. I found a pretty thin shim that was for a Kawasaki (I think).

[thebottle]

Thanks, good advice, my Yamaha dealer didn't have any and couldn't get any for weeks. The Kawasaki dealer let me exchange them.

And great news, 210s are a perfect fit for it so I'm very happy today, . Was really worried there.

[crazy steve]

If you haven't already done so, I'd adjust the valves to the high side of the spec (.010") to allow for them to 'seat in' seeing how you have fresh machining.

[DiverRay]

If the head is still off, you CAN shave a few thou off the end of the valve stems to help with the clearance. Remember, the valves with get TIGHTER as they wear, so you DO need wiggle room. I shaved stems on Special Ed's machine when I did the rebuild. I've seen no problems with the engine so far, and it's FAR from "stock".

[MPittma100]

Too Late

It may be too late now, but your machine shop should provide the proper lash when the head/valves are redone. You simply take the cams to them along with the head at time of repair and tell them what lash you need for the valves. You should not have to do any shim work after the shop has completed the repair.

[IanDMacDonald]

It may be too late now, but your machine shop should provide the proper lash when the head/valves are redone. You simply take the cams to them along with the head at time of repair and tell them what lash you need for the valves. You should not have to do any shim work after the shop has completed the repair.

Mmhmm. They did mine.