Rattling Aero80

[nh_scooter]

So ive read a few topics about rattling, and really hope mine isnt experiencing the "death rattle", so im looking for some input. I recently picked up a 1983 Aero 80. It was missing the variator, clutch and belt so all i could check was that the engine ran well (without any load whatsoever) and the body was in fine shape. fightingplankton was great and sold me the drive components i needed.

I put the needed parts on and durring its first test ride around a parking-lot scooter vibrated pretty bad just as the clutch is grabbing, once i opened the throttle enough the acceleration was great and the vibrating wasnt as noticeable. I didnt take it above 15mph since i dont know when the last time it was ridden. Anyone have any ideas what it could be, or what i should check?

[Wheelman-111]

Greetings:

Sometimes it's just a loose heat shield or a centerstand buzzing on the cases. If that is ruled out, dismantlification to check for slop in the main, big-end, and little-end connecting rod bearings is required. Running the engine without a variator or a belt may not be a good idea.

[fightingplankton]

did you sand down that rear pulley a bit? it had some pitting. i dont know if that would cause a rattle though, but if the belt isnt riding evenly it makes one think it would cause some vibration.

[Wheelman-111]

Greetings:

I just re-read:

scooter vibrated pretty bad just as the clutch is grabbing, once i opened the throttle enough the acceleration was great and the vibrating wasnt as noticeable.

This suggests an issue with an out-of-round clutch bell. It just j-j-j-* as you take off?
When you said "rattling" I thought of slop in the bearings or really bad piston slap.
It might be considerably less complex.