new valve & 215 Shim still out of spec, knock off tip of valve, custom shim?

[Snake2715]

Ok

No sob stories etc. I have been busy with work, divorce, buying house, etc and am just getting to this project again.

1998 GS500 < 9000 miles

Last year I had this post where I was working on the cam chain tensioner and didn't release it.. when I cranked it it bent a valve:
http://gstwins.com/gsboard/index.php?topic=65246.msg782931#msg782931


Got the parts in, the shop repaired and installed/ground the valve, new guide etc.

Over the last few weekends when time permitted I put it back together. The left exhaust shim was out of spec. It had a 255 installed before I bent the valve. I have placed a few orders now slowly ordering smaller and just today installed a 2.15mm shim.. My finger over the spark plug hole it does build pressure, but doesn't seem as much as the other side. I have not put a compression tester on it yet, but the valve is out of spec and too tight still.

I still with the 2.15mm shim cannot get my .003 mm feeler gauge under it. The bucket spins freely and has spun even with the 255 installed when I first put it back together.

So in brainstorming what next? Is the head really shot? I called Dave at the machine shop who did the work last fall and he said he doesn't have the info in front of him, but there may be specs where he can knock part of the valve tip off. He asked if he could bring the head back into him Saturday or next week.

I called another person who said for racing bikes you can block and grind the shims down a few mm to probably get it into spec.... That I am losing a little compression since the machine shop that did the valve work apparently ground the valve that far into the seat... but given I am not racing I should be ok.

Figured since the internals of the engine I am not as familiar with I would run it by the forum and those with GS500 experience.


Any thoughts, suggestions, input or alternate ideas? I imagine I can get custom shims made or these ground. The bike is low miles and I am actually surprised that it took it that far when installing the new valve.

[bmf]

Hi,

It's quite common for a machine shop to take a small amount off the end of the valve to make up for the valve seating deeper after a valve job.

regards

Brett