Unfortunately, it does not appear that this bolt would be compatible with the Monster Moto Classic 80cc (MM-B80) Mini Bike. It looks like the clutch bolt for that model would be an M6 X 1.0 X 16 flange bolt. Sadly, we do not carry a bolt with those exact specifications (all of our M6 x 1.0 bolts are shorter) but you may be able to find one at a local hardware store. If you'd like to look at all the parts we carry for the MM-B80, take a look at the model page here: https://www.monsterscooterparts.com/brands/mega-moto/models/mm-b80


Additionally, on that model page, you'll see an orange "View Manuals" button underneath the photo of the mini bike. If you click that button, you can view both the Owner's Manual and the Parts Manual for that mini bike.