Don't feel bad about your limited mechanical knowledge, you never know you can do anything until you try it. I've got a blown transmission on my dirtbike right now, and I thought the engine was too complicated to disassemble on my own. It's overhead cam, mechanically counter-balanced, has 3 levels of reduction, and all of the parts normally external to the engine are internal. Alternator, transmission, and clutch are all inside of the engine cases. The job requires some special tools, 2 are quite expensive. I figured out how to make them all using a bolt and some lead solder. I am saving myself over 300 dollars doing my own labor.