Valve Gap.

4 replies to this topic
  • taksx

Posted October 08, 2011 - 07:57 PM


Hi Gang,

I'm working on my valve gaps. I tend to set them on the tight side of the ratio.
I have my Intake set at 0.10, and my Exhaust at 0.20. Should I open them up a bit or just leave them alone? will there be an advantage going something like 0.23 on the Exhaust, and 0.13 on the Intake?

Anyways Valves have been solid for the past 3 years not much movement :thumbsup:

Thanks, Eddie

  • MANIAC998

Posted October 09, 2011 - 02:54 AM


Eddie, I doubt you could notice any difference in engine character by opening up the clearances slightly. But in theory, more clearance gives you a miniscule amount more bottom-end grunt. Again, being as it's a single cylinder, I doubt this will be noticeable. What you might notice is a little bit more noise coming from the cylinder head. And you will gain additional run-time between when valve adjustments are necessary. But three years is pretty darn good!!! Maniac

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  • Sknight

Posted October 09, 2011 - 10:00 AM


It's common practice to tweak valve lash to fine tune a power curve but we're talking directly measured on an engine dyno (Not rear wheel but direct off the crank.) and results in <1% range. Tighter means the valve opens sooner, is open longer, closes later and opens more (You get more lift with a tighter gap.) in the process. Wider gap is the opposite.

I tend to shoot for dead even or .001 or so wider to give a little more room for the gap to change.

If it's not changing and you're happy with how it runs I'd leave it alone. Lots of work for what would amount to a miniscule difference.

  • taksx

Posted October 11, 2011 - 09:12 AM


Very thanks for your reply's, Yeah I been lucky the valves have not "walked" on me very much. Yamaha build a good engine.
For now I will let them be and keep checking them as time goes by.

Lets ride, Eddie :thumbsup:

  • Flagstaff

Posted October 16, 2011 - 08:55 PM


I tend to set to the loose side, but hell, with the WR I check'em but don't have to adjust'em.


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