Sounds like you should be looking for a snowmobile engine as the CVT is standard for that application. A 800cc two stroke twin could be quite exciting in a scooter chassis...:huh
The snowmobile clutch is also probably the size of the current engine. The ratios are way different. I would think that for cooling go to a liquid cooled engine and you can mount the radiator up front. Many motorcycle engines have transmissions that are integral to the motor. And many scooters have engines that are "layed" over.
Do you have Kwaka Ninja 250 motors plentiful around your place? Amazing what you can do with an angle grinder (for the gearbox), a puller (to remove the alternator, then make an adaptor for the comet drive sheave), and a welder (to stop it running away in terror from it's new home). The other option is a complete 160-ish cc scoot motor from Taiwan over Ebay, only 15hp but then you're done.
This is a 16 hp V-twin Briggs and Stratton ,electric start and stepless belt transmission installed under the body of a Cushman . This B&S has been warmed over and puts out 25 or so hp now. The bike will go over 80 mph if, you are brave enough.
It's not mine . There's a group of hot- rod guys around here that got into these. Most have the type cushman with the exposed ebgine between your legs. This one was built by my friend Chatlie with the enclosed style bike. Why ? He found one at a good price and wanted to be different that the rest. He hasn't experienceed any cooling issues that I know of. But for him this is a toy, no long road trips are taken on it. The jackshaft set-up has been trouble free. To use it with a swingarm would require stetching the whole package.
Here you go mate, more pictures for ideas in one spot than anything else I've found. Very, very cool stuff here if your into scoots..... http://www.lambrettainnovation.co.uk/view_page.php?pid=178
Well I WASN'T into scoots. Now this whole evening is shot. Thanks. I especially like the "RG 500 4 CYL Wide Body..."
Latest "Scooter" magazine (here in Oz) has a V4 2-stroke made by a Spanish company using 4 race barrels from the Minarelli stuff. V4, 350cc, 110kW (I think, around there anyway).......in a Gilera Runner size scoot. Hehehe!
That's a classic, for sure. Love those old '50s scoots. Engine-wise, with gears, my personal opinion (valued highly by my children, as you can imagine.......): LC singles and geared - WR250R/X. Good power, reliable, light, LONG service interval. AC singles and geared - TTR250, XL250, SR400. If you're going for a true "twist-n-go" auto single, it's really hard to go past the Piaggio Quasar drivetrain, very smooth and understressed, huge aftermarket, but the Kymco 250cc G3 drivetrains are slightly rougher in operation although they have excellent reliability and performance. Having said all that, a Ninja twin would be cool.
This is very interesting to me. I am currently building a 1975 RT-1 Rokon and will use an 18hp Briggs & Stratton for the power. My engine will arrive soon. Any tips?
