I have been looking into the use of a complete snowmobile motor in a Banshee-style frame.
The advantages are simple: high horsepower in a stock motor, good drag racing powerband, a literal plethora of aftermarket parts including EFI turbos, reliability, an auto clutch, etc. I have seen both Rotax 670 and 779cc motors used in drag bikes (Tom Hill runs a low 9sec. 1/4 mi. in a nitrous 670 with nearly 300 hp and I have seen several 100yd. sand bikes in Michigan running the 779cc motors).
However, many of the guys I have talked with- such as Doug Kurtz of D&M Racing in Phoenix- say that the entire motor won't work. Supposedly the engine vibrates too much and causes the clutch belt to break, and the clutch and flyweights are a nightmare to set-up.
My question is, have any of you either tried using the entire snowmobile motor or seen any others using this set-up? It is clearly a promising alternative to high maintenance drag Banshees who must run override trannys and rebuild top-ends every couple weekends. I am hesitant to jump into this project without more information.

P.S. Ohton: I was up on Sandy Hill Easter weekend and have to say that your bikes are impressive, anyone on this site considering motor work should give your shop a call. I had Tony Leon port my bike and it runs really well but am looking into something more powerful and reliable- either the snowmobile motor or a Kahn-built turbo 4 cyclinder. Any suggestions? Also, what is Sal Cobrales running on the CR500 quad that you built besides alky and nitrous? Thanks.

 

The problem with a snowmobile engine is they are ment to run in cold temps, so they have smaller cooling capacity due to the added cooling of the cool air. So you try running the engine in the summer, it will over-heat in a hurry, and no a larger radiator won't help, because the cylinders are made to flow less coolent. When the snowmobilers grass drag in the summer, they don't run them for very long, but they still do everything possible to keep them cool enough not to overheat. Thus I wouldn't recommend it.

Good luck with whatever you do, I am doing my own project also (YZ400F powered quad), so I know what its like wanting to do something like that.

Sickman

 

I have a friend who put a 700 Polaris engine in his 250r other then the width of the engine making it a little less comfortable to sit on the bike he rides it like a regular 4 wheeler he jumps it does tree shot and Yes drag races up the bowls at the dunes He does have aftermarket shocks to soak up the extra weight and he does put a new belt on every weekend but that is cheap maintence for how fast his bike is.
since this creation he has built a scrambler with the same engine and he is also building another scrambler with a 800 polaris (by the way he works for a polaris dealership) and he is building a Quadzilla with I believe a 800

 

What exactly did he do to make it work? Was it only a matter of fitting the engine into the frame and how well does it cool? Any other info would be greatly appreciated as well.
One more question, from what I have heard, Dennis Packard built a triple cylinder snowmobile motor in a quad several years ago. Anybody have any info on that bike or know if it is still around? Thanks

-Mike

 

I have watched him make about twenty races up the hill before stopping to let the engine cool down. As far as fitting it I believe all he did was cut a few bars out add a few bars. Then he put a Idler shaft that the belt hooked to with a sprocket & chain to the 10" extended swingarm

 

Coming from a guy who races snowmobiles on the grass, and rides them all winter, i have given the idea some thought too. I figure my STOCK 700 yamaha triple makes about 145 hp, and put a port job and a set of triples on it and you are flirting with 200 hp out of a still very reliable motor. The one issue i have come across is lining everything up in the chassis. I don't have much fabricating experience so maybe this is easier than i thought, but lining up of the clutches is critical to transferring power to the ground. Also the center to center distance of the clutches is crucial to have exactly right.

If you don't have any experience tuning clutches, that can have you beating your head against the wall too. There are literally thousands of differnt set ups and if you have no prior expereince, you are going to have trouble.

I would reccommmend contacting some of the snowmobile shops and talking to them. Bender Racing in New York is a excellent yamaha shop. they have a web site, although i don't know the adress off the top of my head. Another good place to try would be PSI Performance. They specialize in building highly modified "crate" motors that bolt into sled chassis. They have some wild stuff that might be just what you are looking for (1500 cc 250+ hp motors).

 

One other thing, as far as the cooling problem, we get around that during grass drag season by using a cooler with a bilge pump it it hooked up to a set of lines with couplers on it. after making a run, we hook up the lines to a coolant line that also has a set of couplers. flip the swithch and the bilge pump pumps out the hot water into the cooler full of ice, which melts the ice and sucks back in cold water. And, in 30 seconds you have a motor that is cold to the touch.

 

That bull I've set up 3 quads with sled motors never have they overheated long as u have a rad with a fan ur golden