Intake Valve Clearance Close - Adjust?

2 replies to this topic
  • RichB

Posted January 03, 2002 - 05:54 PM


Hey guys, I just checked the clearances and had one exhaust valve out of spec barely on the tight side. This is my first valve adjust job so if I'm reading the manual right and I have a 189 pad and my measurement was .178 is should need a 185 replacement pad (I think I got that part down).

My real question is two of my intake valves measure just inside of spec near the tight side of the scale. Would you guys go ahead and open them up or leave them closer to the tight end of the spec?

Thanks in advance

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  • ossagp

Posted January 03, 2002 - 08:57 PM


I like to run mine on my four strokes on the looser end of the scale. I have not had a new yamaha though.

  • Boit

Posted January 03, 2002 - 09:23 PM


That seems reasonable to me. Since the shims come in denominations of .05, you are loosening that valve less than a full increment.

I've noticed that stock machines come with some in-between size shims. Perhaps we could all start an inventory of different shim sizes and could swap amongst ourselves and get that exact size we want? When I checked my valve lash intially, I recorded all my shim sizes. I have three 1.79's and two 1.80's.

When my valves get close to the "tight end" of the range, I would prefer to open it up just a little rather than .05 in one fell swoop. An in-between size would be just what the doctor ordered here.

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