You are better off just keeping the bike original especially if you have no access to welding equipment and tools needed to modify a frame. Do some research on you motor take it all the way apart because a bike that is close to 30 years old will need what was stated above. New seals and if you want to kit it new bearings. And since the original owner used jb weld on the head is a good idicator it will need a tear down. Even if you find the internals destroyed you at least gain knowledge of the engine internals and how it works. Then you can worry about getting the parts to make the motor you have work or finding a used motor to get back running. The nice thing about tomos is they are still being made so new parts either stock or performance are abundant. Maybe start with making the stock bike perform better for your style of riding and as you gain knowledge upgrade and kit it. This will save you time and money and gain you experince.