Welcome!You can buy pretty much every part for the 4-stroke Marathons.The engines tend to need Head-Work or Rings.There have been issues with the cam-gears,so check that out if you go inside.The spot to check the frame is the crossmember below the front of the seat,where the swing-arm attaches to.Its' not real common,but that is the spot that seems to rust out when they do.Hope this helps.