Whine or whistle coming from engine

[bad mechanic]

I've noticed a new sound from my bike in the past couple weeks. It's a soft whine or whistle coming from the engine under power. It goes away when I close the throttle and pull in the clutch. In other words, it's there when the throttle is open, or when the bike is decelerating under engine braking.

The sound starts once it warms up and after the oil has been pumping for a minute or two. The sound goes away for a minute if you stop the engine, wait a couple minutes, and then start it again.

I've gone over the engine with the stethoscope, but didn't find anything, except a faint whine from the front left side of the case.

Right now I figure I'll ride it until it gets worse.

[smrookie]

Do you have the fcr carb?

[Craigo]

So is it running ok?...If so you may have a turbo or supercharger lurking in there......lol

No seriously, if you have an Fcr it may be induction noise, but that would audible only under acceleration...

Perhaps it's cam chain/ACCT related issue, got an MCCT fitted?..How many miles on the engine?

[bad mechanic]

It's the stock carb with the DynoJet kit, 3x3 mod, and full FMF exhaust.

It runs great! In fact, so far it's been the most trouble free bike I've had. It has 9,500 miles on it.

I just ordered a MCCT tonight.