View Full Version : Need help with some fine tuning!

02-02-2010, 04:09 PM
After some megalogging and some trail & error fine tuning my bike runs awsome and extremely cool! went on a very intense 30 miles ride, killed the engine and the fan didn't turn on(!) as well as no popping what so ever on closed throttle.
But, I've noticed this weird and very annoying rummbling sound when the throttle is just above it's closed position. Very noticeable when cruising at midrange and trying to decelerate just a bit.
Has anyone here experienced such a thing?

02-02-2010, 05:08 PM
It's really hard to tell without actually hearing the "rumbling" sound in person.

Since it's happening on the decel, and your bike is obviously running very cool, I'd guess you're just running rich. Not enough to cause the distinct popping, but perhaps just enough that you're getting some residual burn in the exhaust.

I'd maybe adjust the mixture just a little leaner in that RPM/Throttle range and see if it goes away. To be honest, if it fixes the noise, I'd probably still adjust it back to where it is now. If that's truly the cause, then you're better off running slightly rich on decel rather than too lean.

Anyways, just a wild stab in the dark.