I've done a search here on Yamaha's ultramatics, but none answers my question. (I'd ask a dealer, but somehow I believe I'll get a better answer here). What's the difference between Yamaha's belt drive system ("Ultramatic") and the other belt drive quads, if any?[img]i/expressions/face-icon-small-confused.gif[/img]

 

Yamahas ultramatic trasmission is different, all other companies automatic transmissions except honda is like a snowmachine where the primary clutch ingages onto the belt directly where yamahas the belt is always engaged and the primary clutch is attached to the belt drive. Hope that made sence.

 

The yamaha and the suzuki (suzuki made, not twin peaks...its kawi), and most a/c( but not the 650 h2, its kawi also), are all very similar. The belt never goes slack on the pulleys. Its the proper tension 100% of the time. They use a centrifical clutch at the end of the crank, to allow idleing in gear at a stand still. The drive pulley is staionary, until the rpms get up to 1800 rpm or so, and then the centrifical clutch takes over and spins the pulley. On the polaris and kawi, the drive pulley opens, and the belt falls slack, just like on a snowmobile, to allow idleing in gear. The drive pulley is spinning when ever the motor is spinning. The downside to this, is when you hit the gas, the drive pulley spins faster, and closes forcefully on a belt that is stationary . If you are in high gear, and theres a load ( hill, towing, mud, two riders etc), theres gonna be alot of slipping going on. The belt on them, is consumable, and is considered the clutch, as it provides the slip. They also are much noisier than the constant tension types. and tend to run warmer due to the friction and slippage.
Its necessary to run those quads in low range, for slow going. The yami , doesnt require using low, because if the belt is dry, it wont slip, in any range. Its optional to use high or low.
To provide engine braking( in which the wheels drive the motor), there is a sprag clutch, which only transmitts force in one direction, and free wheels in the other direction. So when the motor is producing power...the sprag clutch is free wheeling, and as soon as you let off the throttle, the sprage will engage and slow things down. Its almost as good as a gear drive tranny, it happens right away, and doesnt kick out at low rpm or mph. The kawi and polaris use different methods for engine braking, which act differently than the yamis. They arent bad...just different. They sometimes need a goose of the throttle of stay engaged, because of the way it applies engine braking. The yami never needs that goose to stay engaged.
The belts on the yamis will last a very long time, provided it is kept clean and dry. The newer quads do a vey good job of keeping the belt dry and clean.
Theres a side benefit to the yami system...even though it is belt drive, if you want to bump start, or need to bump start, it allows this to happen. Also in the event the motor dies, coming down a steep hill, it still will provide engine braking...just like normal.
I thought I wouldnt like a belt drive tranny, but after buying a kodiak last year...I 'm hooked. Yami does make the most dependable, and quiet Belt drive CVT.

 

Great write-up Hondabuster!!!!!!!! I learned a lot from your write-up.

 

Thanks, FastbansheeandKodiak and especially Hondabuster. Now I wonder how Yamaha can claim their Ultramatic is exclusive if Suzuki and possibly others use the same scheme. Being a control freak, especially in steep downhills, I'm trying to remove my bias against automatics, and your responses really help. There's a lot of prejudice against belt drives, but all the manufacturers use them, except Honda, so they must be pretty good. Thanks, again, all.

 

hondabuster is correct, the belts on a yamaha typically outlast any others. as long as you dont sink it over the racks (ony once...) the belt will never slip, and i put a good 5200 miles on mine before i replaced it for... reassurance. having 5000 miles on a single belt scared me as to how much life it could have...

 

I used to think I would never own a rubber band machine, and after reading up on them, and driving them, I knew the polaris and kawi werent for me. But the yami acts like a geared machine, for engine braking...its almost as strong , engine braking as my foreman. Its very reliable, and I dont carry a spare belt, and dont even think about it.
If you can...ride one, and ride a kawi and polaris too. Its nice when you get in the tough stuff, because you wont have to worry about being in the powerband, or worry about sticking your leg into the water to shift, its always in the proper range.
They arent like snowmoblies, where the engine is reving to redline, to get moving...if you go slow in high range, it can creep along at 2200 rpm, almost like a geared machine.

 

Should of looked before posting. So then essentially the New KQ should not have to have the belt changed like people are doing, manual says change it, but to me that is a money racket as they are very pricey compared to the Polaris and Kawi belts.
So the KQ should be getting 5000 miles before really needing a new belt, under normal circumstances. Of course big tires and work loads will decrease this.

Thanks

 

well belt wear varies depending on how you ride your machine. you could possibly get 5000 miles from your belt or you may get 3000 miles from it. i havent owned an auto for a long time so i coundlt tell you much about all the new systems

 

Well said hondabuster!