So I purchased a really nice 1981 Yamaha IT 175 for my collection and have a couple of questions (always been a 4-stroke owner ;>). What is the proper fuel-oil mix ratio for this machine, 40:1, 50:1 ? What is the proper spark plug, I read online to use a NGK B9EV I also need a idle screw and lock nut for the Mikuni carb. I believe its a VM34 model but not sure . The idle screw is on the left side, air mixture is on the right . Idle screw should have a lock nut . Where can I find a new one of these ? Planning on doing some AHRMA racing with it....oh yeah and it has a street legal title too....yikes Thanks for any help !