installed a nx650 cylinder and piston, but now it vibrates a lot.

Hi guys, i'm wondering if anybodyelse that has ever installed a 640cc kit on his XR600R has nitticed that vivbration.

I got a used NX650 dominator cylinder that i made bore to 101mm and got a 10:1 wiseco piston.

The bike goes very well, but as the rpms reach 4000rpm or so it vibrates a lot, then after 4k it seems that it softens a bit and at around 7000rpms you can feel the vibration harder again.

It's because the stock XR piston and the wiseco doesn't weight the same or what?

Should i take it apart and grind some material away from the new wiseco piston to make it weight the same as the stock XR???

Or that vibration is normal and can't be softened?

Thanks a lot.

I used a NX cylinder in my old XR 600R

a NX cylinder but with a 101 XR piston (JE), not a NX piston

the XR piston is 1mm taller than the NX piston, because the stroke of the NX (like XR650L) is 2mm longer than XR 600

Hi guys, i'm wondering if anybodyelse that has ever installed a 640cc kit on his XR600R has nitticed that vivbration.

I got a used NX650 dominator cylinder that i made bore to 101mm and got a 10:1 wiseco piston.

The bike goes very well, but as the rpms reach 4000rpm or so it vibrates a lot, then after 4k it seems that it softens a bit and at around 7000rpms you can feel the vibration harder again.

It's because the stock XR piston and the wiseco doesn't weight the same or what?

Should i take it apart and grind some material away from the new wiseco piston to make it weight the same as the stock XR???

Or that vibration is normal and can't be softened?

Thanks a lot.

If you are experiencing vibration, you are correct that there is most likely an imbalance in the engine. Most likely due to a change in weight of the upper end reciprocating assembly. Hopefully you still have your old piston, rings, & pin. If so, you can pull the new parts out and have them match balanced to the old stuff and that should fix your problem.

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