Bonneville America Forums Forums Technical Forums Performance Mods Valve Shim Gap

The last(and first) Shim adjustment I did, I put them in the middle of spec.

Is there any performance increase keeping Gaps on the minimum side or large side?

Large on exhaust? Small on intake? Visa-versa?

Thanks,,,,,,

No.
Perhaps if you had a multi many dollar racing engine and you are looking for every 1000th of a horsepower, but on these just keep them in spec.

Hey thanks.

I plan on keeping everything in Spec.
.15-.20 Intake and .025-.30 Exhaust

Right now I run .17 and .27.

I'm sure my bike will run quieter if I keep demensions closer to the smaller numbers.

And everthing would stay open longer with the minimum numbers(suck and breathe more).

I may have to check the gap more often than every two years, I have no problem doing it.

I think i just answered my own Q.

I keep mine on the lower side to keep the rattle down. I makes no difference on performance though.