I found that when I took apart my original engine, it was so worn out, it was too expensive to buy all the parts to do the rebuild. It needed a rebore, new pistons and rings, new main bearings, big ends and possibly con-rods. It also needed a new camshaft and followers, an oil pump, cam chain and tensioners and work on the cylinder head to fix the bearing surfaces where the camshaft runs. The only serviceable parts left were the crankcases etc. In the end I picked up a second hand low mileage engine from an american import bike for