motorcycle engine............

[mymaro]

Okay first off im zipping my flame suit on as i type

I am going to build a mod. I have poked around the internet to find a measly couple articles of running a motorcycle engine in a snowmobile. i can manage most of the fabrication myself. The the only main problem i have as i plan/brainstorm this out is harnessing the power to the secondary? I plan on using a i4 out of a sportbike.(just not the one outa my gixxer) if i were to get a output shaft made for the transmission to fit a primary clutch that would work but what happens if i drop below 5500 rpm without downshifting. Plus a manual transmission in a snowmobile is not very user freindly but it could work. Maybe i could use a cvt transmission but what motorcycles use this transmission not many? Im basically looking for advise about that issue for right now.

Yes i know whatever im smokin must be good stuff. No this is not a midlife crisis. i just want a different mod sled everyone these days have a iqr mountain mod with a wc tripple.

FLAME AWAY!!!!!!

 

[pernikm]

Unfortunately it has been done. It is called an Yamah Apex...A modified R1 motor designed for a snowmobile. I doubt you can do much better...

 

[mymaro]

i knew i was gonna get that.

 

[DeepDaze]

cool, had a friend who put a T.D.I. clean diseal into an edge body, man that thing was fat but it had some monster torque!

Maybe a Cmx belt drive would solve the rpm problem? Or you could just cut a hole in the tunnel and run a foot shift up through there Good luck on the mod hoped this helped

 

[pernikm]

i knew i was gonna get that.

oh! don't get me wrong! I want to see this built!...I am just not expecting better than stock performance. It would never work in the mountains but you are from MN...I have seen Harley Mod snowmobiles from there!

 

[mymaro]

another thing i thought of was what if i were to somehow get direct drive to the crankshaft would a clutch hold up to 15,000 rpms?

 

[AKrider]

I understand you want something different but all the issues you are mentioning have all been figured out by Yamaha. The novelty of a manual shift sled would wear very quickly and simply not perform as well as a stock sled.

There was an article about the development of the RX-1 that showed a Yamaha Exciter equipped with a 400cc street bike motor with a manual trans. Besides the issues with exhaust heat the manual transmission didn't perform well on the snow.

I think you'd be better off using a Yamaha sled motor and installing it into a different chassis. That would be very challenging and still be one of a kind.

 

[triple7]

In short, No or atleast not for long. I would think you would want to select a gear that would warrant clutch speeds of around 8000 rpm at the peak output rpm. I have no expirience building one of these things but it seems to me that you should be able to find a gear in the engine that will produce this. An Apex uses a gear reduction to reduce clutch speeds, but a transmission would accomplish the same thing if left in a lower gear than direct.

Then you could machine an output shaft (and probably an outboard bearing would be a good idea) and adapt a standard clutch right on the motor. From there it is just fitting the thing in a chassis and making it have enough power to be fun.

Just thoughts...

Jake

 

[Norway]

First, what triple7 said! You don't want that clutch to spin more than 9000rpm.

Using the stock tranny takes care of some machining headaches, good idea.

Now for my "grand idea":
Find out what kind of reductions your tranny gives you and see if you can run the secondary clutch straight on the driveshaft like the old Polaris Star.

I think I'd even go down to 7 tooth/2,52" pitch drivers to be able to do that.
No chaincase...

Best of luck, enjoy!

RS

 

[olymon]

Didn't someone build a sled on here with a tube frame, a street bike motor, and an air clutch back about 2 years ago. It was probably lost in the switch over of the forum. There were quite a few pictures of the build. I'm not sure they figured out all the problems with the shifting/gear box. looked like a pretty cool project. I wish I could remember the posters name

 

[mymaro]

In short, No or atleast not for long. I would think you would want to select a gear that would warrant clutch speeds of around 8000 rpm at the peak output rpm. I have no expirience building one of these things but it seems to me that you should be able to find a gear in the engine that will produce this. An Apex uses a gear reduction to reduce clutch speeds, but a transmission would accomplish the same thing if left in a lower gear than direct.

Then you could machine an output shaft (and probably an outboard bearing would be a good idea) and adapt a standard clutch right on the motor. From there it is just fitting the thing in a chassis and making it have enough power to be fun.

Just thoughts...

Jake

thats what i thought. i have to be able to go higher then 8000 rpm. your basically right at the beginning of the power curve of these motors.

i would use an rx1 motor but most of the ones i have found are going for a pretty penny. a sportbike 600/750/1000 can be had for 600-1000 depending on miles.

 

[FTXMOTORSPORTS]

Just input....several years back we raced(hillclimb) and mountain rode a rotax 700 triple that we spun at 10,500 rpm...not once or twice but for several seasons and that clutch/motor NEVER gave us any issues. We also switched to a p-85 on the same motor eventually and NEVER had any issues with it either.That set up is still screaming around and has not had a failure yet!
-my point, dont let the rpm scare you...let the harmonics of a four stroke compared to a two stroke at that kind of rpm scare you!
Now that being said, I'll contradict myself...we tried supreme tool rage 8 primaries last season on a few different mountain triples(1275-1500cc watercrafts) and couldn't keep the clutches alive(clutch bolts either) BUT They appear to live just fine on the yamaha four strokes(as best we can tell anyway)???
Not promoting the use of clutches at that kind of rpm...just relaying experiences!

curt

 

[jas123]

Try pushing your bike around the block,now try pushing the sled.It takes much more power to move the sled.The gears in the trans and the clutch won't handle the abuse.20 years ago a company called Top Gun performance used to do this but without the gearbox.If you are really set on this you need one of these http://www.h1v8.com/page/page/1562068.htm

 

[pernikm]

Efficiency is the reason you don't want to spin your clutch to fast. It is a matter of how many times in a second you bend the belt around the pulleys. The faster the spin the more the loss. My ultra spins 9000 rpm has 180 hp and there is a real reason it has a problem keeping up with modified 900 cats. 10% loss means 18 horse power.

 

[turboDS1300]

Hayabusa sled

Efficiency is the reason you don't want to spin your clutch to fast. It is a matter of how many times in a second you bend the belt around the pulleys. The faster the spin the more the loss. My ultra spins 9000 rpm has 180 hp and there is a real reason it has a problem keeping up with modified 900 cats. 10% loss means 18 horse power.

This is slightly off topic but there was a turbo hayabusa ice drag sled running the circuits in Minnesota this year. I show it run at a local contest and believe he ran just under 180mph in 1000'. Pretty impressive. They ran the "stock" transmission setup running a chain drive to the driveshaft with an airshifter. I believe they are out of Northern Illinois...RPM Cycle maybe?

 

[mymaro]

Does anyone know the gear reduction ratio on the rx1 motors?
I may end up looking for an rx1 motor? also a turbo is stewing in the pot
Im picking up the chassis this weekend and am gonna start making structural reinforcments. its a 95 or 96 xcr 600 chassis. i wanted to use a mid eightys chassis just cause thats different but im getting this one for next to nothing.

 

[diirtbag]

http://www.snoriderswest.com/features/march07/ktminterestedinsnowmobile.htm just in case people havent seen this ,its motorcycle powered

 

[AKCoop]

Don't forget the yamaha 4 stroke (sled) family also uses dry sump oil systems so the engine can sit lower in the chassis.

Yamaha made numerous changes to the R1 motor to use in snowmobile applications.

Check out some of the old forums.

 

[POLARIS600cc]

This is slightly off topic but there was a turbo hayabusa ice drag sled running the circuits in Minnesota this year. I show it run at a local contest and believe he ran just under 180mph in 1000'. Pretty impressive. They ran the "stock" transmission setup running a chain drive to the driveshaft with an airshifter. I believe they are out of Northern Illinois...RPM Cycle maybe?

I believe in one of the mountain mod vids, there is a turbo'd busa motor in a sled. They were racing it at big iron or one of the like races.

 

[theultrarider]

thats what i thought. i have to be able to go higher then 8000 rpm. your basically right at the beginning of the power curve of these motors.

i would use an rx1 motor but most of the ones i have found are going for a pretty penny. a sportbike 600/750/1000 can be had for 600-1000 depending on miles.

He was refering to the rpm of the output shaft of your transmission not the engine rpm! The tranny ooutput shaft rpm= the rpm of the sled clutches, not the engine rpm. Thus your gearbox in the bike motor becomes your "gear reduction" if you pick the right gear to run it in. Probably 4th gear.....