Yamaha automatic scooter to power 21’ banka.

Planning a 40’ banka but right now would like to power my 21’. At this point I am wondering why I could not salvage the drive train from an automatic scooter (125 cc) and install in my boat. I have even imagined incorporating an outboard lower end to use as differential, giving me reverse capability. The scooter would have its own electrical system with push button start. Thoughts?

 

Same problem with using motorcycle engines to power aircraft, they usually have a transmission integrated into the engine cases that isn't useful for powering a boat. The gearing ratios are not appropriate (in planes, they turn to slowly, in a boat, too fast). Now if this motor is the kind where the CVT is also the swingarm for the driven wheel, and you can remove it to have nothing but an output spine shaft, then things get doable. an adapter plate is fairly simple. But I don't know how you'd get a motor's output shaft that is coming out at 90° to go "down" an outboard lower end at 180°. Engines really don't like to run in any orientation other than the way they were designed (carburation, lubrication, etc.).

You are better off selling the scoot and buying an actual small outboard motor.

 

Thanks for your thoughts James. As you suspected, I was planning to use an automatic with CVT. I was thinking to leave motor and swing arm installed on the original frame of the bike, cutting away all unused portions. With rear wheel removed I would perhaps have sufficient space to install (by hook or by crook) the lower end of a small junked outbord motor. End result, with any luck, would be a motor I could electric start but not engage prop until I add power (as opposed to the other bankas I see around that pull start and are immediatly producing thrust, so no nuetral or reverse). The electrical system is a bonus! This would be a proof of concept for my 40’ I will build later this year. Thanks for your interest in my project. Bill