Needing help to build a "Boonie-Bike"

Hi all,
I'm wanting to begin a project that entails some things that I have little experience with. The project is to build a sort of "Boonie Bike" .... which is basically a Mini-bike, but on a larger scale. I'm thinking of using a front end off of an old 3 wheeled ATV, with the large, wide tires, and I will probably have to fabricate the remainder of the frame - unless I can find an existing one that would work.
The first few questions .... of what will no-doubt be many is; has anyone here, ever taken on such a project, and if so, what would be some of the considerations, based on your experiences with this type of thing?
I'm thinking of just using a conventional horizontal shaft type engine (i.e. Briggs), in the 8 - 10hp range - to keep costs 'reasonable'. I'm not really looking for much 'speed', but I'd like to get 25 - 30mph out of it. It will mainly be for 'off-road' use, so I would want some lower-end torque, for moderate 'hill climbing' ability. Not sure what type clutch I should use .... centrifugal, or torque-converter(?) also, could anyone recommend a type of tubing, that should be used for the frame?
Appreciate any and all advice anyone could provide, to help get things rolling.
Steve

 

Hi, I just finished building just that kind of a mini bike. For the application you described a torque converter will be the way to go. If speed is not the big concern with this mini bike use a large rear sprocket. If it seems too slow you can always make the rear sprocket smaller. {less power- more speed }. Check out the Comet torque converters with the one piece mounting for the drive and driven clutch. No jack shaft needed.You can get tubing, axles, bearings, bearings flangettes, bearing mounts, brake rotors and calipers, sprockets,wheels, hubs and just about anything else you might need at:


http://www.bmikarts.com/gokarts-mini...er-parts.shtml

I used a large atv tire on a 8" rim for the rear so I hade to make my own swing arm from square tubing to fit that tire. The coil spring mini bike shocks for about 18.00 each worked real good.
Best regards, Jeff Z.