Lets hear all the crazy ideas in the back of everyone's heads. Personally I think a 500-800cc v twin smoker fuel injected with a cvt, custom frame with the track coming under your feet would be the ticket. 137+ track could be similar in overall length to a kit 120. Have heard some rumors that BRC has this motor ready to go for whoever wants to make a production bike, but who knows. I think a 100 hp and 300lbs would be great but likely out of reach for a home build. I enjoy the snohawk concept but the geometry just looks really off to me. I have been considering if a polaris atv 400cc 2 stroke would be worth messing with. some of the drag racing sites claim they get 75 hp with a 440 BB and supporting mods but I wonder if it will hold together. If it would I imagine the narrow cvt motor would be an interesting option. Anyways Lets hear everyone's thoughts!
Lets hear some creative home build ideas
- Thread starter 2smokin
- Start date
I looked into the Polaris 400 2stroke also.
Problem is they were notoriously unreliable in stock form (42 ish hp) and modding them made them worse.
The union bay racing 450 single 2t cvt snowbike looks like it would be a good test mule for viability.
I think the 600 vtwin chilling at brc needs to be persued.
Ok hear me out. Take a cat laydown twin (intake, exh on the same side), put a belt drive on the PTO, which drives a CVT mounted on a shaft just behind the engine. The CVT belt center line would be in line with the center of the engine. Secondary also in the center with a normal jackshaft to chaincase setup. Pull start could be mounted on the primary shaft as well, to narrow it up further. Engine mounted on top of tunnel where a gas tank would normally sit on a sled. Exhaust up and over the top.
Would be a long /tall but narrow setup. I think?
Would be a long /tall but narrow setup. I think?
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N
Another member here is doing something very similar to what you propose.
N
Sounds great! One problem, such an engine doesn’t only vTwins are heavy 4 stroke street bike motors. But, keep thinking. That one guy that grafted two cr500 into a v twin 1000 seemed like a cool, and redonkulous, build.
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Sweet. Any more info on it?
N
Not yet. He will probably chime in here at some point. I don’t want to blab about his project ideas, but they are definitely creative.
The biggest challenge that I see is keeping the bike narrow. I’ve noticed that in tight quarters the drag on the sides of the bike is what leads to trenched stucks so making the bike any bit wider at all is just going to make that a whole lot worse. Of course that’s only in deep snow, but that’s where we want that extra HP so? That is the big issue.
We have a lot of room for things to live where previously there were wheels however. Mainly in the front by the exhaust. If that area could be utilized for HP gains in stead of widening then that’s the direction I’d like to see us go. But, regrettably, that engine just doesn’t doesnt live on earth in any kind of realistic scope.
I’m tempted to fly to Europe and find a damn maico 700 engine somewhere lol.
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C
No need to fly to Europe. Just have them ship it to your door. :face-icon-small-hap. https://zabel-motor.com/en/home/
I know I posted this before but does look, light ,narrow , fuel injected, and extractable gearbox
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Figured that would be the issue with the Polaris, that union bay bike is pretty much exactly what I was thinking minus the unnecessary frame area. Where did that engine come from? It’s a shame that the Brc motor is just waiting, but I can understand them wanting a real manufacturer to sell to not just the ten people that might want to make something work. Would be nice to see some R&D though.
What is this called? Is it just a concept? Looks tiny but the configuration would work if you could get the cvt set up. The Aprilia rsv250 was a v twin smoker made until somewhat recently, I just don’t see why you would bother with a peaky twin two stroke without a cvt on the snow, if we are going to have to shift we may as well have some torque! Even my old rd400 has a fairly sad bottom end don’t think it would be too great on the snow unless you worked the clutch hard.I know I posted this before but does look, light ,narrow , fuel injected, and extractable gearbox
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Supposedly it’s a ubr 900 cut in half.
Claims 90 hp.
Claims 90 hp.
Interesting, not that 90 would be impossible but seems a tad high, would be interesting to see some details on how the motor came to be.
N
The cvt bugs me in operation, I like the direct connected feel of gears on the ground. But there are obvious reasons for a cvt sure. Then again one of the main issues cvt faces is altitude change compensation, where gears don’t even know.
2 stroke powerbands and cvt go hand in hand. Yea the feeling sucks, I agree.
What about an electronically controlled cvt that allows de-clutching. A 'clutch' lever on the bars that opens the sheaves and allows you to dump it (within reason). pop up the front end over creek crossings etc.
Not so sure how that would work but it would certainly be interesting, i do enjoy the direct gear feel other than the lack of ratios when you need them.
M
Even if its the best solution, I have no interest in a CVT on a snow bike, to me that just makes it nothing more than a skinny sled.
M5
M5
N
There are other ways to achieve cvt, and even some that don’t rub as much heat as the belt squeezy things sleds use.
Put indy dans clutching on a stock axys.
Instant ski lift in any situation / maximize trackspeed for a given throttle input.
Backshift to “first gear” in an instant, then spool up the track to 40 mph a second later.
It’s all about proper calibration.
You can hold your hand on the clutches after a hard climb.
(For reference I cannot hold my hand on the transmission case of my ninja 636 after a hard climb ??)
As much as I like riding this thing every time the track isn’t accelerating (shifts) the momentum needed to make the next turn/ climb/ cliff etc. isn’t happening.
Yes i can rev it, slip the clutch, upshift/ downshift etc.
Cvt by definition will apply power to the ground more often and with smoother power progression (traction) than a manual gearbox.
Now compare to a stock sled from 2006 ish?
Clutching is trash, sled drops rpm with increased load, recovers slowly.
Belts are constantly wearing out, you can cook an egg on the clutch.
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