Vibration after twin disc clutch install...
 

Just installed twin disc clutch and flywheel. Now have vibration... most noticeable at 50 mph. If clutch is disengaged while driving, vibration goes away. Am thinking vibration is related to flywheel balance. I was told that it could be one of two things:

1) The stock flywheel may not be zero-balanced... and by replacing it with balanced flywheel, a vibration would result. Would first need machine shop to check if stock flywheel is not zero-balanced. To fix, the new flywheel would need to be sent to machine shop to have it mimic the balance of the stock flywheel.

2) New flywheel and/or clutch assembly is out of balance. Need to replace with a good (balanced) unit.

Are there any other reasons for vibration? What's the likelihood of having stock flywheel not being zero balanced?

If you swapped the clutch but not the flywheel you might need to get the flywheel resurfaced.

just out of curiosity why did you keep the stock flywheel?

Sounds to me like he replaced the stock flywheel and is concerned that the new flywheel is not balanced the same as the old flywheel.

Who did you buy the clutch from? Most twin disc clutches come marked by the manufacturer, did you line the paint pen lines up on the pressure plate and flywheel when you installed it? If not it could cause some vibration.

I'll check for the markings when it's taken apart.

Update: Markings were lined up and stock flywheel confirmed zero-balanced. Working on another solution...