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New Technology Comes to Future Yamaha Snowmobiles!


Sooo, I had my calculator out again and it looks to me like the gear reduced Genesis 1000 FI has the perfect mix of a wide torque band and the right scope of ratios to make a direct drive snowmobile, finally become reality! If the present primary clutch sheave diameter is completely used (belt runs all the way to the top) and the secondary clutch diameter is increased by 60mm., the chain case and jackshaft can be eliminated and the secondary mounted directly to the driveshaft. The break rotor and caliper could then be mounted directly to the other end of the driveshaft, similar to the Arctic Cats F series design, which has proven to perform well in the stopping department, even without the gear reduction advantage of the chain case gears and jackshaft.
Click to expand...

Don't take and give us a smaller secondary please like AC did! Also don't even think about using a design like the Diamond Drive, it's not anymore efficient than the chaincase! It may drop some weight, yes, but IMO it just doesn't cut the mustard for Yamaha's cutting edge technology! We know what you're capable of so give it to us! 60mm isn't much to ask on the secondary diameter (just 2.36'')!


Yamaha, are you listening? Now you can loose another 10 kilos of weight from sled and reach significantly closer to the weight of the injected 2-strokes you are targeting for weight! It will work…. Granted, no reverse but who cares…I’ll take it!
Click to expand...

Stroker, not only would it be a significan't loss in weight, but you also failed to mention the movement of the weight lower in the chassis. This is going to lower the center of gravity some and will once again improve the handling.[/quote]
 
Great post SS :Rockon:

With around 50% drive train loss, this where engineering needs to go next, I agree completely. I think track design and something that eliminates the hyfax could be looked at too.
They could put on some sort of electric motor reverse like some of the motorcycles do if that was the only holdback issue.
 
Track design has a huge impact on the loss in horsepower. Hook our track dyno to the driveshaft (eliminating the track) and I think you might just soil your shorts to see how many HP that big rubber band eats up!

Have any of you paid attention to what the mountain guys are doing? They're cutting all kinds of 1'' holes in the middles of their track! What does this do? It frees up HP by allowing the track to rotate easier and also loses some rotating weight as well. Now will it work out in the trail, I'm not sure and if I knew I wouldn't die if my track exploded, I'd try it myself! LOL!

Also if the I'm correct then there is another plus in my book. The track acts like a big fan pushing air and snow in the tunnel, it has only one place to go normally, out the front. If you can let the air and snow escape from the inside of your tunnel the track will spin faster.
 
Allen,
McLeod said they did 10 sleds in their group with the holes, some did square holes to save even more WT.
One thing they noticed is with the back up in the air and the sled running the track did not turn on its own. After the holes were drilled the track did turn by itself with just that little bit of friction against the non engaged clutch.

That says spinning resistance is lessened quite a bit!!

Anybody on trails do this yet??
 
Tork, I'd like to try it on a trail track, but my brain keeps telling me not to. My biggest fear would be hooking something and ripping it. Ski Doo has introduced this as a production item on their Summit "X" package for 2006. I may try it next winter, but maybe on something with lower hp to start out with (nytro or vector)? I don't want to give up any safety or durability just for the sake of a little bit of performance gain.
 
I was thinking about 1 hole down the center, that way I could still stud. :D

John did say that the tunnel has less snow to push, so that is a tie in with your other post and an additioal benifit.
 
Srxspec said:
Sooo, I had my calculator out again and it looks to me like the gear reduced Genesis 1000 FI has the perfect mix of a wide torque band and the right scope of ratios to make a direct drive snowmobile, finally become reality! If the present primary clutch sheave diameter is completely used (belt runs all the way to the top) and the secondary clutch diameter is increased by 60mm., the chain case and jackshaft can be eliminated and the secondary mounted directly to the driveshaft. The break rotor and caliper could then be mounted directly to the other end of the driveshaft, similar to the Arctic Cats F series design, which has proven to perform well in the stopping department, even without the gear reduction advantage of the chain case gears and jackshaft.
Click to expand...

Don't take and give us a smaller secondary please like AC did! Also don't even think about using a design like the Diamond Drive, it's not anymore efficient than the chaincase! It may drop some weight, yes, but IMO it just doesn't cut the mustard for Yamaha's cutting edge technology! We know what you're capable of so give it to us! 60mm isn't much to ask on the secondary diameter (just 2.36'')!
Click to expand...
[/quote]

O.K., I'm not nearly as experienced with sleds as you guys, but I have a few thoughts. Maybe a fresh look would be good...or maybe my inexperience will show itself. We'll see.

What about a better replacement for the variable transmission (belt & clutches)? Those two clutches are heavy and its been proven that a belt drive such as snowmobiles use is one of the weakest, and more important, most inefficient design available. It worked well for the 2-strokes because they required the engine to stay at a very narrow power window, but with the 4 strokes, we need something more efficient and lighter.

For gear reduction, whats wrong with using a planetary setup like an automotive automatic transmission, or a 4x4 transfer case? No chain to loosen and wear out, or break. A planetary in an automotive transmission is lighter than the combined chain, gears, and can handle the power of a big block or diesel. You could make one even smaller and lighter that is safe to handle 300 HP, and use it. That would also eliminate a shaft, because a planetary could be installed on the end of the drive shaft. Someone tell me if this is what Cat already calls their Diamond Drive...I'm not familiar with it, but if its not working, then they are screwing something up, because its a very simple, light weight design that would be extremely durable.

Jim
 
60mm isn't much to ask on the secondary diameter (just 2.36'')!


Yup...2.36 inches on the diameter is only 1.18" (30mm) of additional sheave and that's not much, is entirely reasonable in terms of sheave stability upon engagement!
 
How about computer controlled clutching. Think about the possibilites of having several pre-programmed clutch curves. One for racing, one for trail riding, one for economy, etc. Yamaha is capable of this technology. Replace the torque sensing helix with load cells to actually measure the load on the track and for the primary replace the weights with a servo controlled actuator. Food for thought. Use your laptop to create a custom shift curve......
 
one of the downsides to mounting the secondary on the axel is the ability to change gear ratios.i would like to see a belt drive replace the chain.it would be cleaner(no oil), lighter, and more effecient. ratios could be changed with pullys making it work for all the sleds in the lineup. both yamaha and cat used fluid drives on models in the early 70s, and this is probably another option.
 
I investigated the belt drive option for my ZRT because that sled went through WAY too many chains. I averaged 500 miles out of a chain before it stretched, or worse yet, broke. I even tried heavy duty D&D chains with no better luck. The belt drives looked awesome, but they were big $$$.

Jim
 
There is not enough room below the drive shaft for even the stock clutch much less a larger one. That is why the diamond drive can work, With the planetary they can run a smaller diameter driven clutch and get the ratio through the planetary. Not that i am a fan of the Diamond drive though and gearing option's are big $$$$. I like the belt drive idea and i think there could be a lot more improvment to the CV type clutch(bring it to 2006 standard's) to put more HP to the ground. SRXSPEC i would be real interested in your result's with the hole's in the track, Could releave air pressure in the tunnel and help with slide lube at the same time as well as reduce rotating mass. I knew a person with a 440 SSR with a track cut to 9" that redared in the low to mid 120"s. As you said, New tec in track and clutches and WOW!!!! 130's for the Apex. kviper
 
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