Any of u gt owners ever try using an ss engine or a rotax motor seems like it would be better than hopping up Briggs I'm almost considering buying a gt just to try it I don't have that option with prodrive but if I did I don't think I would put a penny in a Briggs if anyone has done this I would like to se pics and see how they perform ? how fast?

Yep..both have been done.

The Harley engine needs constant air flow to keep cool...which is a set back unless you also rig it with a radiator of some sort. The other setback is clutches. The clutches that are used on these motors aren't capable of withstanding the power/torque that the Harley engines emit.

As for using Rotax engines, Kyle at GT had one at Mud Fest back in '06 or '07. It had lots of top end (ran 50-55 mph) but sucked royally on the bottom, as Rotax engines need to spool up pretty high before producing power.

all you need is a new motor bracket with a 90* gear box from the shaft on the engine to the vertical shaft


Marty(basinhunter) build a GT with a harly engine clone (IIRC) but had problems with the clutch holding up.

I heard he was working on a prodrive also.

I figured the ss engine would have heat issues when u stuck in mud just seems like some one out there could build something better than Briggs something with 70 plus horse power

I have always been interested in this. but have just not had the time to get involved.
having 1 or 2 e-fans would help with the heating issues. they have some pretty power compact fans on the market, 2,000-3,500 CFMS.

i have a 700 street bike motor i wanna make a surface drive .looking for ideas

Cooling would be easy, big oil cooler and fan! Like Craig said, clutch won't hold up, solve the clutch issue and I think it would be fairly easy....