Flywheel noise?

I've been riding my '02 in the woods with an aftermarket 12oz flywheel practically since I got it and never thought much of the whirring noise the bike makes, I just figured that's what a big bore Yamaha sounds like. Now I've recently bought an '01 that I've left stock as a track bike. It has the stock flywheel in it and there is no noise like my '02 makes. Is it possible the weighted FW could be making that noise? I thought it could be the timing chain too but it has a self tensioner right?

mabey the weight is viberating.

whats the noise like? is it a supper fast tick? and is it for sure coming down by the fly wheel?

Just had a buddy of mine, who's also a mc mechanic, come over and listen to this noise. He says it's either a main bearing going out or possibly some piston slap from a worn out piston. If it is the piston, which I sincerely hope it is as apposed to a total engine rebuild for the main bearing, what brand of piston to you guys recommend for this bike? He says the Wiescos' are loud so stick with OEM. Is there a third choice to consider?

Check the bearing on the left side of the balancer shaft. The shaft can be removed and inspected in the frame. Main bearings could be at fault, but they're pretty hefty, and should make more of a growl than a whir.

i would choose Wiesco. what do you meen loud?

Check the bearing on the left side of the balancer shaft. The shaft can be removed and inspected in the frame. Main bearings could be at fault, but they're pretty hefty, and should make more of a growl than a whir.

I pulled off the magneto cover tonight as I changed the oil and checked for any play in the balancer shaft, flywheel and crank....there's none. Any other suggestions as to what could be making this noise. :applause:

I was doing a search and came across this thread.

I've had my flywheel weight on my bike for about 2 months and it does the exact same thing you are describing. Sounds almost like a turbo whine. I just figured it's because of the flywheel weight :thumbsup:

I was doing a search and came across this thread.

I've had my flywheel weight on my bike for about 2 months and it does the exact same thing you are describing. Sounds almost like a turbo whine. I just figured it's because of the flywheel weight :thumbsup:

I never discovered what the noise is on my bike but I ruled out the flywheel when I checked the bolts on it and they were tight. You might want to do the same, especially if it's getting louder with time.

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