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Need help Identifying vibration

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I need help identifying source of vibration from our 11.

Its got a high frequency vibration which is enough to shake various frame and sub frame bolts loose.

So far I’ve swapped the crank and mains twice. First time with Hotrods products, thinking I might have got a out of balance crank or bad bearing, and the 2nd time OEM. To no avail.

I’ve just ordered both balancer shaft bearings, and the clutch bearing and sleeve.

What else could I be missing?

Thanks in advance for any suggestions

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Improperly manufactured piston that isn't of the proper mass? Did you change the piston, and then this started? Both rod-end bearings ok?

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im only familiar with 02-08, but if (it same) balancer gear and drive gear dots may not be lined up.. if not, you get some crazy vibration.

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Edited by MELK-MAN

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Its acted the same way with 3 different pistons and I looked everywhere for a frame crack.

I also know about lining up the balance points and checket that as well.

I'm going in tonight to see if I can feel any play in the balance shaft bearings, but since the bike only has 28 hrs, I wasn't expecting a worn bearing unless it was defective to begin with.

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I wasn't expecting a worn bearing unless it was defective to begin with.

A piece of machining crap could have fouled the bearing shortly after you got it. I would think that would make a lot of noise then too.

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Well just got through removing both side covers. I can detect no free play in the balance shaft at all.

What I did find is a lot of looseness in the clutch basket.

It will rotate forward and back about 1/16" before the drive gear shows any movement and before making contact with the cushions.

The cushions are really loose. The rivets are tight at least.

It seems like the needle bearing which the basket rides on is loose as well, since the whole assy has a lot more movement than I'd like to see.

Don't think I've ever seen a clutch with such low hours in such bad shape.

I guess this is what I get for cutting corners, and not taking the clutch off the shaft, when splitting the cases.

I'm suprized the clutch could cause the frequency of vibration we're getting, since is spins at such a reduced rate of the crank. I'm guessing 4.? to 1.

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Had a similar issue with a engine vibration on our 250 that got real obvious after installing a lighter flywheel. First though it was the lighter flywheel but later discovered the clutch basket cushions had gotten quite loose, also there was some notching in the basket. Replaced the old basket and the vibration went away. See post #17. A good aftermarket basket with replaceable cushions seems like the way to go.

http://www.thumperta...09663-flywheel/

Edited by TDW

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I was looking into that and it sounds like the cushions are the same, but with the OEM basket being notched it wasnt something that would last long, also the OEM basket may need to be drilled first to get the correct size and then threaded.

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