I just picked up a 1984 moto 4 80 cc yamaha for the grandkids. The rear end is out sounds like ring and pinion.I was wondering what years and sizes can I interchange the whole rear with thx

 

Take a look in the Yamaha section. someone in Sweden has just fitted the rear end from a "Chinese copy" into their little Yam due to rear end failure. https://atvconnection.com/forums/yam...ar-axle-2.html If you want to go genuine Yam, check the part numbers in on-line parts lists of your rear end compared to Raptor 80s etc.