Valve adjustment help....

[Agent4573]

So what do you do when you're already running a 200 spacer (the smallest they make) and still can't get the correct gap? The bucket spins almost freely under the cam, but I can't get my .038 feeler gauge in there. I think its running rich at idle, but until I can get this correct I don't wanna mess around w/ the jets. Also, at high rpms it seems ok, but once it drops below like 3000 rpm you can see it start to spit fuel back out the carb from the valve not seating completely. The other buckets are running 225, 235 and 240 shims. If I swap buckets around do you think it might make a difference?

[coll0412]

that means that head needs to have some work done. You could try and swap buckets, but the valve seats are probably toast anyways.

[ben2go]

Time to buy a used head and rejet.

[beRto]

curious... what is the year/mileage on the bike?

[gsJack]

Standard Suzuki replacement shims range from 215-310. If you have a 200 someone must have put in an undersize shim already, don't think I'd go any smaller than that.  I used to record them as .001" and let them go if I could turn the bucket freely with my finger tip.

If your other shims are 225, 235, and 240; I think maybe someone shaved the head on that bike to raise compression, they seem to come from the factory with shims close to 260, at least my 2 GSs did.  I've put over 130k miles on them and never required a shim change on the intake valves.  The 97 GS went 88k miles w/o intake shim changes but one exhaust shim was dpwn to the 215 minimum.

A good used head assembly just might be the best way to go.

http://img.photobucket.com/albums/v443/jcp8832/valveclearances.jpg

[Agent4573]

It wouldn't surprise me if the head had work done because this is an ex racing bike. The 1st head I took off the bike(had a blown head gasket) looked like it had been dropped and there was a gash in the mating surface. Upon checking the P to V clearance,  I didn't have enough to deck the head anymore as it had already had work done to raise compression. This second head looked really good until I tried to get the valves adjusted correctly and couldn't get the gap. I found 29mm shims down to 2.00mm online and got a 2.00, 2.05, and 2.10 to complement the 2.15 I had laying around. If i couldn't see gas coming backwards through the carb at idle I would let it go, but that just doesn't sit right with me. There is a post on here of a guy getting rid of 2 heads for 40 a peice. I figure I'll get one of those and hopefully it will work. I'm assuming that as you wear away the valve seat you go to a thinner and thinner spacer, so having a valve job done would do nothing for me except make the problem worse, correct? Being that its so close right now, would it be possible to take some sand paper or a grinder to the inside of the bucket or top of the valve to take the .05mm off that I need to?

O yeah, I have no idea how many miles are on the bike, but I would say somewhere in the range of 70k. With probably 10-15 of those done on the race track.

[gsJack]

Actually I misspoke above, shaving the head wouldn't affect valve clearance but grinding the valves and/or seats would require thinner shims.

If you have the head off and apart you could consider grinding off the valve stems if you can grind them square.  The old flat head Fords of the 30's and 40's didn't have any shim or screw provisions for adjustment.  We would reface the valves and grind the seats and then grind off the valve stem to restore proper clearance.  The flat head Ford V8 came out in 1932, same year as I did.   

Looks like you could grind off enough to get back to a normal range of shims, that's what I was considering doing on my 97 GS when it got to a min exhaust shim thickness but I ended up totalling the bike and replacing it with the 02 GS instead:

[gsJack]

By the way, 29 mm dia shims are for Kawi and would be loose in the GS buckets.   GS shims are 29.5 mm dia and fit better and would be less likely to be thrown.

http://www.crc2onlinecatalog.com/valve_shims.htm

You probably know that and got the 29 mm because they come in thinner sizes than the Suzi ones.   

[Agent4573]

Well we're gonna try grinding down the valve a bit. Worst that happens is I still have to get a new head, and I just take a valve out useless one I have sitting here when I rebuild it again. Thanks for all the help.