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Main Area => General GS500 Discussion => Topic started by: GSinUS on April 29, 2006, 08:52:39 PM

Title: No clearance on exhaust valves
Post by: GSinUS on April 29, 2006, 08:52:39 PM
I have no clearance on the exhaust valves (shown by the fact that the cam followers are not rotating when the lobes are pointing upward).  I am a little confused here.  How can I calculate the size of a replacement shim in this case?  The fact that there is no clearance means that the valves never close completely, effectively decreasing combustion pressure, correct?

Also, one of the intake valves is tighter that .038mm but the cam follower turns.  Unfortunately I don't have a gauge smaller that 0.038.  What woiuld you recommend I do here, leave it alone?

Thanks very much for all suggestions.  BTW, I had difficulties removing the valve cover.  What helped was, like others suggested, using a piece of wood as a chisel and gently tapping on it with a hammer.
Title: Re: No clearance on exhaust valves
Post by: The Buddha on April 29, 2006, 08:58:49 PM
1 size smaller shim, then run it a bit and check ... then 1 size down again ... I'll do it that way ... shim when dropped in floats on oil ... dont get good reading.
Cool.
Srinath.
Title: Re: No clearance on exhaust valves
Post by: GSinUS on April 29, 2006, 09:39:26 PM
Errr, I don't have any extra shims at hand, I was hoping to order only ones I need.  So this means I have to get a bunch of smaller shims just to figure out which one I need?  And also in order to run for a bit, to get a correct reading, do I need to reassemble everything and turn the ignition on? Am I understanding it right?

Thanks
Title: Re: No clearance on exhaust valves
Post by: Egaeus on April 30, 2006, 05:19:55 PM
Quote from: GSinUS on April 29, 2006, 09:39:26 PM
Errr, I don't have any extra shims at hand, I was hoping to order only ones I need.  So this means I have to get a bunch of smaller shims just to figure out which one I need?  And also in order to run for a bit, to get a correct reading, do I need to reassemble everything and turn the ignition on? Am I understanding it right?

Thanks

Did you watch kerry's video?  What he did was use a 215 shim, and calculate it that way.  Worked pretty well for me.  The formula is:

215 shim clearance + 2.15 - 0.05 = desired clearance.  Round desired clearance, preferably to the loose side unless it's too loose.  That's the valve shim you need.