Hi has any experienced a flat spot or surging feeling like the bike is about to run out of petrol at lower revs between (2to4k) at a constant throttle, Is there a fix for this ?. Also is there a mod for the seat as i feel it tips you forwards towards the tank ? thanks Gary.

It does run a bit lean in that rpm range. You could check your throttle bodies' vaccum synchronization. A vaccum gauge is needed...

This happened to me yesterday. I thought the bike was out of fuel at first. I pulled over revved it up a few times. It took off just fine as if nothing had happened. I tried to convince myself that I was daydreaming and didn't know what gear I was in. I hope its not going to be an issue.

Happened to me!

I'd say its probably the EPA-mandated lean mixture in that range causing imprecise fueling. My solution is to ride at 4000 rpm and up. A few extra revs on this motor seems to give more flywheel effect and smooth out the power pulses.

A Power Commander may solve this issue. I have one on my trackbike and it fuels perfectly from bottom to top.

TPS adjustment and vacuum hose mod cured my low end lean flat spot.