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Crf250l vibration after supermoto wheel conversion

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New mods- put on warp9 rims with 140/70/17 in back, 110/70/17 in front, stock 14 front sprocket, 40 back sprocket(came with rim). Using stock chain. Also put a kouba lowering link(shorter rider).  Now the vibration on foot pegs are numbing my feet after about an hour of riding.  Is that normal.  Very new to motorcycle riding.  I did try throttling it in neutral and it does vibrate but not enough for me to notice an issue.  

The Crf250l has 600 miles with mods-ejk, air box holes, k&n, 3.1 gallon gas tank and yosi full exhaust.  Didn't notice numbing vibrations with stock rims and tires.  Thanks for any info

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When I put my Shinko 705's on, I took off down the highway and had a lot of vibration, almost felt like square tires. Turned around and went back home. Put the tires down from 22 psi to 10 psi. Took it back out on the highway to spin them up and let centrifugal force get the tires where they need to be on the rim. Went home and put 22 psi back in them. Smooth as silk and fantastic ever since.

 

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The wheel were not balanced for reason of the rim color(red) and sliver weights(only ones the shop carries).  The motorcycle runs smooth at low rpm.  Bad vibration starts at higher rpm.  Don't seem to matter in what gear.  Someone recommend to going 50-60mph and holding clutch to let it cruise and to see vibration stops.  Tried that and the vibration seem to be gone.  Would out of balance wheel do that?  Bad rear sprocket cause it happens in gear only?  Chain look straight and tension look right.  Torque everything down I could think of. 

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On 4/30/2017 at 3:12 AM, Dall said:

The wheel were not balanced for reason of the rim color(red) and sliver weights(only ones the shop carries).  The motorcycle runs smooth at low rpm.  Bad vibration starts at higher rpm.  Don't seem to matter in what gear.  Someone recommend to going 50-60mph and holding clutch to let it cruise and to see vibration stops.  Tried that and the vibration seem to be gone.  Would out of balance wheel do that?  Bad rear sprocket cause it happens in gear only?  Chain look straight and tension look right.  Torque everything down I could think of. 

That sounds like what mine is doing and has been doing for several thousand miles now. Lots of vibration at highway speeds with heavy engine load, but reducing throttle or clutching kills the vibration completely. I'll be watching here to see what you discover...

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On 4/29/2017 at 3:30 PM, Evan D said:

Ive seen out of round sprockets too.

I'm new to motorcycles.  Do you mean worn out sprockets?  

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1 hour ago, Dall said:

I'm new to motorcycles.  Do you mean worn out sprockets?  

No, just poorly machined. I've seen the outer not being true (round) and I've seen the mounting pattern (the mounting to the wheel hub) not being centered so that when bolted on it went around wobbly.

 

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11 minutes ago, Evan D said:

No, just poorly machined. I've seen the outer not being true (round) and I've seen the mounting pattern (the mounting to the wheel hub) not being centered so that when bolted on it went around wobbly.

Same with tires ..... sometimes they are just out of wack from the manufacturer .... :rant:   it happens        

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The fact that the vibration goes away when the clutch is pulled - in effect uncoupling the engine from the chassis - leads me to believe that it is the engine where you will look for a cause of the vibration. Balance shaft ? If it was a chassis related cause, clutch in or out would not have such an effect, so too wheel bearings, sprockets, wheels and tires, etc.

Edited by seedy
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After about 1000 miles of riding since noticing vibration issue and trying many things.  I'm thinking with all the modifications that's how it going be.  Thanks for all your inputs.  

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You need to check the tyre is on straight and that the wheel is balanced. You won't feel the inbalance with the clutch in. First rock the bike up on the side stand and prop the swinging arm so that the rear wheel can turn. Slowly turn the wheel and look where the bead of the tyre enters the rim. To check that the tyre is round and fitted correctly.

I had a tyre clamp on my wheel that threw my wheel way out of balance. Your aftermarket rim may be doing the same. I balanced my own wheel and stuck the weights inside the rim in the wheel well. You can remove the wheel and spindle and mount it in a home made wooden frame with bearings supporting the spindle. Spin the wheel if it stops in the same place every time its out of balance. add weight opposite stopping point untill it stops radomly. My "Jig" is made of pallet wood. The bearings were very cheap on ebay. Get 8 or 6mm centres to fit your bolts.  I use the same jig for wheelbuilding.

 

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