If you check out my minibike build video,
I installed rubber washers (grommets) between the engine & mounting plate.
This is something I first did when I was thirteen.
I complained to my dad, who told me that Harley-Davidson reduced this problem by isolating the motor from the frame with rubber.:thumbsup:
It can only be done with round mounting holes.
If you are using the guide holes, the motor will vibrate and loosen the chain right off.