Re: new to the motorbicycle world
Welcome to the forum. We're glad you've joined us.
Rubber: Don't use it! Inserting rubber or any resilient material between the engine and the frame is a mistake. You will not eliminate or reduce engine vibration but you will transfer it to the mount fasteners which will cause more vibration and eventual fastener failure. I know the theory sounds good, but it doesn't work!
Do a little research using our search feature and you'll see what others have posted on this subject. It isn't a new issue but has been discussed here countless times. Listen to the experienced builders who know and ignore the marketing hype.
Good luck with your motorized bike project. Have fun and ride safe.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"