Grassfirebob
Pro
Just pondering. How come dirt bikes have geared transmissions but all snowmobiles use CVT's?
Since the RX is basically the same engine as the R1 bike... why not use a geared transmission?
Since the RX is basically the same engine as the R1 bike... why not use a geared transmission?
SoCoRX1
TY 4 Stroke Guru
my guess is that you change speed way too much that an auto transmission would wear QUICK and a manual would get annoying when trying to climb a hill or boondock
JDKRXW
TY 4 Stroke Junkie
Centrifugal CVT's are;
1) Simple and easy to fix
2) Light
3) Cheap
4) Don't need a manual clutch (which would need to be huge in a sled)
5) Work pretty well in very cold weather
6) Work very well with narrow power band 2 stroke engines because they sense torque (and react to it) very well
1) Simple and easy to fix
2) Light
3) Cheap
4) Don't need a manual clutch (which would need to be huge in a sled)
5) Work pretty well in very cold weather
6) Work very well with narrow power band 2 stroke engines because they sense torque (and react to it) very well
Grassfirebob
Pro
What I don't get is that there are strong similarities between riding a dirtbike and snowmobiles (at least the way some ride).
If it's good for dirtbikes......
If the arguments for lighter, cheaper, etc... apply to snowmobiles...then why wouldn't they use CVT's on dirt bikes?
(Ok, I'm bored, no snow to ride, and it's late at night ... that's why I started this topic! lol)
If it's good for dirtbikes......
If the arguments for lighter, cheaper, etc... apply to snowmobiles...then why wouldn't they use CVT's on dirt bikes?
(Ok, I'm bored, no snow to ride, and it's late at night ... that's why I started this topic! lol)
mikeb
Expert
They did at one time. Honda had a 440 street bike with a "automatic" and Rokon had a 370 dirt bike wth "automatic". Both got ok reviews but ......... CVTs dont give you is precise control or good low RPM performace.
Both models are not more
Both models are not more
RX1 Yooper
TY 4 Stroke Junkie
The are more efficient also. Some small cars have them. They put one in a grand prix car, and it turned faster laps.
Red2003
TY 4 Stroke Guru
Yeah, that all makes sense, but wouldn't it be awesome to have a 6 or 7 speed attached to that 1000 cc four stroke! That and a kick starter and I am in heaven! I bet another big reason against it is that a standard would limit who would purchase and drive the vehicle. Gas and go is easy to drive for everyone. A standard tranny option would be great though. Think of the compression you'd have. Come into a corner, drop it down a couple gears, slide in and wide open out. It sure would sound cool heading down the trails grabbing gears as you go. Man I want to make one now.
kmer
Expert
Red2003 said:
Now THAT would be a vision to behold...
ReX
TY 4 Stroke God
A guy I know built one several years ago.
On the trails the manual gearbox had lots of potential, but off trail it wasn't ideal (huge variation in track speed - there is lots of spinning in deep snow - very easy to bog the motor down between shifts and get stuck).
He also had lots of trouble with the controls. I think he had a shifter rigged up on one foot and the clutch on the other. With big clunky boots on you can imagine some of the issues.
It was very fast though. I think it had a 1200 cc Suzuki engine/transmission or something similar- and this was in the days when a 500 cc liquid was considered fast.
He used a chain drive from the engine/tranny to the jackshaft (small gear) and then another chain between the other side of the jackshaft and the driveshaft. He had to gear it up (large gear on the jackshaft, small gear on the driveshaft).
The chains were not enclosed - typical motorcycle setup.
On the trails the manual gearbox had lots of potential, but off trail it wasn't ideal (huge variation in track speed - there is lots of spinning in deep snow - very easy to bog the motor down between shifts and get stuck).
He also had lots of trouble with the controls. I think he had a shifter rigged up on one foot and the clutch on the other. With big clunky boots on you can imagine some of the issues.
It was very fast though. I think it had a 1200 cc Suzuki engine/transmission or something similar- and this was in the days when a 500 cc liquid was considered fast.
He used a chain drive from the engine/tranny to the jackshaft (small gear) and then another chain between the other side of the jackshaft and the driveshaft. He had to gear it up (large gear on the jackshaft, small gear on the driveshaft).
The chains were not enclosed - typical motorcycle setup.
monker
TY 4 Stroke Guru
Think about the riding you do. I know my feet are moving around all the time. Sitting, feet back/standing/sitting, feet forward. Plus those big bulky boots. Maybe an elec. trans. like the Honda quads. Then again, I have enough trouble adjusting my handwarmers with my left thumb. I guess I'll stick with the cvt.
grader
TY 4 Stroke Master
a cvt set up keeps the machine in the proper 'gear' all the time for max hp and torque. those that have put cvt drives on bikes (not factorys) have said they were faster everywhere. when you hit the gas its full power non stop, no gears to change. snowmachines have too much rolling resistance to make a gear box work. what i would like to see from yamaha is a belt drive setup to replace the chain/gears/oil or better yet a direct drive to get rid of it all. these 4 strokes produce lots of low end torque and proper sized clutches could compensate for the gear loss. the diamod drive cat uses sounds good on paper but seems to rob top speed and is noisy(more gears and oil) and i hear about failures more often than not. i think the belt drive would work best, as pully changes would be clean and quick, and cover everyone from racers to flatlanders to mountain riders.
mclarenyamaha
Pro
we have one v-max 4 with an turbocharged yamaha r1 motor in it. it works awesome. he has buildt in an electroninc gearshift like the motogp class has. it gears upp automatically but down he have to use the clusch. he has done a really nice jobb on this one only 460 pounds race ready. the engine has it own frame around. and he has also built his own rear suspension. trust me this guy now whts he is doing.on the lazer he has 210 kmt on 4th gear,and then he have two gears left. and beliwe me he will pull them both.
Grassfirebob
Pro
As sleds become more "rider forward" (which is basically mimicking the way you ride a dirt bike), I would imagine that your feet will become more stationary.
As sleds evolve more over time it makes sense to me to have the controls eventually be similar to a dirtbike and/or four wheeler. The biggest holdback was the "sitdown" style that sleds have always had.
Once we're into a riding position similar to cycles/4 wheelers - some manufacturer will get bold enough to go out there and try gears/twist throttle, yada yada on a model.
Just my 2 cents.
As sleds evolve more over time it makes sense to me to have the controls eventually be similar to a dirtbike and/or four wheeler. The biggest holdback was the "sitdown" style that sleds have always had.
Once we're into a riding position similar to cycles/4 wheelers - some manufacturer will get bold enough to go out there and try gears/twist throttle, yada yada on a model.
Just my 2 cents.
MR.HAPPY
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A high & low gear would be sweet!
BR
BR
Bakemono
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The reason you dont see CVT on a motorcycle is because it would throw the balance off too much.
Look at an automatic ATV (Polaris or Yamaha). They have the big CVT housing that sticks out to the side. On an ATV its no big deal because balance isnt as critical. On a bike it would throw everything off and the bike would have a tendency to want to wander to one side or the other.
Its a proven fact that an auto tranny is faster. In Formula 1 right now they are using semi-automatic gear boxes and the lap times are faster than they have ever been.
Also, a CVT is much more efficient than a manual tranny because it can give you an infinite number of gear ratios. A CVT always keeps the engine in the heart of it's powerband. Also, when you hit the gas on a CVT it goes to maximum rpm right NOW. With gears you either have to downshift or wait for the engine to work its way up to max rpm. Then you have to shift and wait for it to come up again. With a CVT it stays at the rpm that gives it maximum power and stays there.
Efficiency is the reason why you are seeing more and more cars going with CVT. 2 of them that I know that use CVT are the Toyota Prius and the Ford 500. I think there are some others that use it too, but I cant think of what they are right now.
Hebi
Look at an automatic ATV (Polaris or Yamaha). They have the big CVT housing that sticks out to the side. On an ATV its no big deal because balance isnt as critical. On a bike it would throw everything off and the bike would have a tendency to want to wander to one side or the other.
Its a proven fact that an auto tranny is faster. In Formula 1 right now they are using semi-automatic gear boxes and the lap times are faster than they have ever been.
Also, a CVT is much more efficient than a manual tranny because it can give you an infinite number of gear ratios. A CVT always keeps the engine in the heart of it's powerband. Also, when you hit the gas on a CVT it goes to maximum rpm right NOW. With gears you either have to downshift or wait for the engine to work its way up to max rpm. Then you have to shift and wait for it to come up again. With a CVT it stays at the rpm that gives it maximum power and stays there.
Efficiency is the reason why you are seeing more and more cars going with CVT. 2 of them that I know that use CVT are the Toyota Prius and the Ford 500. I think there are some others that use it too, but I cant think of what they are right now.
Hebi
