Knacking

[Neil E.]

So what do you do to stop it? The theory seems to be that it is from unburnt fuel pulled into the exhaust while on closed throttle. This ignites with a bang when the throttle is opened again.

I'm down to a 38 pilot and still get it. A friend with a 300 gets it all the time and he rides a lot faster than I do. Some guys have said it clears up if you take the bike for a rip. That's not easy to do where I ride, and I'm always back on single track right after going down a forest road. With terrain changes it's impossible to avoid closed throttle running. Pulling in the clutch to let the engine idle doesn't seem to help.

[Neil E.]

I was out riding yesterday and we had a spectacular fall day, rare for late November. After the ride I was talking to JP4 about his 2010 300 (not the same friend as in the first post). He commented that once he had leaned his jetting out enough, the knacking stopped.

[Jakobi]

I find the same thing. When opening while rich it burbles. When opening while inbetween it claps or knacks. When its just right its just right. I do expect it to happen a bit though.