valve specs

[Pontiackid73]

valve specs for an 01? I remember reading to leave the exhaust a little loose but i cant find the post with the specs.

Also over time do the tolerances get looser or tighter?

[bombsquad83]

0.03mm - 0.08mm on all valves.  Some people run looser on the exhaust to prevent burning a valve with longer times between shim changes (including myself since it was that way when I bought it).

The clearances get tighter (smaller) with wear.

[gsJack]

Valve specs are the same for all years.  It's been my experience over many tens of thousands of GS miles that the intake clearances rarely change while the exhaust valve clearances get tighter.  One of the exhaust valves in my 97 GS that ran on the tight side of tolerance required more and more shim changes after 40k miles and was down to a min 215 thick shim before 80k miles with no place to go.  When the tighter exhaust valve in my 02 GS began the same process around 40k miles I began setting the exhaust clearances wider to allow more cooling seat time and the valve recession progress was all but stopped.  Now at 92k miles on the engine I expect to go to 100k miles on mid size shims, if I last that long.   

I set my valves now at the stock .001-.003" (.03-.08mm) for the intakes and a looser .003-.005" (.08-.13mm)  for the exhaust.  The stock .001 (.03mm) minimum specked clearance is unusually tight for air cooled mc engines.  Here's the whole log of my GS valve experience:

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

[Bluesmudge]

gsJack, how many times have you had to post that reply?

[burning1]

I think he can copy and paste it at this point, and I'm glad he does. A lot of people complain about the valve adjustment intervals on the GS, and his info really helps that.

I adjusted the valves on my race bike to his suggestion. After a season of racing, they were still in spec. Never had an issue, despite occasionally running the bike to 12K RPM .