Hi everyone, ive been researching extensively and building and rebuilding this "minibike", but keep ending up wit too tall of gearing. When riding it, it feels like a Bonneville salt flat contender. Its a 1984 Suzuki DS80 that I got with no engine. I had a couple of horizontal Techumsehs laying around but they were only 2.7hp motors. The suggested gearing was 5:1 or 6:1 but they assume rear tire dia. when making those suggestions. I chose the largest rear (72) and smallest clutch in #35 (12) resulting in 6:1. But, with a tire dia of 18" (56.5 circumference) its still WAY too tall of gearing. So last night I swapped the 2.7 for a 5hp and its way better but not good enough. I don't mind fabbing up a jackshaft and was thinking a 14/12 gearset that would give me a ratio of 7:1, but I wanted to throw it to you guys as Im tired of doing things trial and error (and expense)
Need gearing help with unusual father son project minibike
Turtle, welcome to the site. You could also play around with a TAV system that may improve your final ratio.
Either way, here is a link to one of our member's jack shaft calculators. I've used it quite a bit, and it might help you to narrow down some gear options should you incorporate a Jack Shaft. Also, I believe you can get an 11t Max Torque clutch from OldMiniBikes Warehouse. (link above, they own the place)
http://www.parduebrothers.com/minibike/ratiospeed.xls
Either way, here is a link to one of our member's jack shaft calculators. I've used it quite a bit, and it might help you to narrow down some gear options should you incorporate a Jack Shaft. Also, I believe you can get an 11t Max Torque clutch from OldMiniBikes Warehouse. (link above, they own the place)
http://www.parduebrothers.com/minibike/ratiospeed.xls
