Yamaha, there is a possibility of someone getting hurt with these SW primaries!

[HighSpeedLowDrag]

The four cylinder Apex has a rubber cushioned drive, with a gear reduced output shaft on it. The 998 will never be as easy on clutches and belts as the Apex was. The Hurricane crank weight would help I suspect, but will still never be as good as an Apex is to clutches. IMO the Apex is/was the finest engine ever put into a snow mobile, tight on its heels was the four cylinder V-Max-4 two-stroke. Both of the best two and four-stroke engines are now gone, and we have lousy 3 cylinders engines with god awful harmonics in its place. Then look at the existing two-strokes and they are now all two cylinders! All the new engines absolutely hammer clutches and belts. We've made steps in reverse, not forwards in this sport.

IMO gear reduced cushioned output shafts are worth the little bit of added weight. You can add power by spinning the engine RPM much higher with reduction output shafts and make life easier on the belt along with running an even longer belt, making life easier on the belt yet again. The old V-Max-4 had a very long belt with long centers!

 

[20/80]

Hard to believe Yamaha has not looked into their clutches for their Sidewinders, where a reputable business like Thunder Products has taken steps beyond to contact them to bring this issue to Yamaha's attention before somebody gets seriously hurt, Yamaha it seems has taken up Textrons code of ethics, Sell you a shiny flashy promoted product then Take your hard earned money and F#$k you.

 

[yamamarc]

Yes, you are so correct!

I haven't even mentioned the TEAM clutches and I have hundreds of pics of those cracking, chipping and TEAM primaries blowing apart. These are coming apart on stock 6000's with hardly any miles.

Something I noticed with mine is the movable sheave bushing was extremely tight. (Wasn't sliding freely. I feel this might have caused the crack on mine!!

Curious> how many miles? The rollers and bushings are trashed.. Not saying or implying anything just curious.
Thanks

This one had 8000km. It was brought to me to go over.. the previous owner didn't do maintenance. Imo

 

[rtx moose]

These are NOT tuned sidewinders I have posted the pictures of and I have information on all of them, even the names and VIN numbers.

The sled in question about the severed brake line and fuel tank punctured was a flashed sidewinder...I am not going to lie about that.

I have hundreds of photos of clutches that have been sent in, that we have worked on personally, seen on FB and have specific dealer information and pics from STOCK sleds.

how many stock clutches have you seen with problems?5-10?50?

 

[Warren Silliker]

I have had 3 explode on me. Once came back threw brake caliper thru foot well and off my ankle. Somehow it didnt break it but was swollen and sore for several weeks and really had a bump there for about 4-5 months. Thunder products does your 911 cover help these issues any by making the towers more rigid? Have you had any with that cover fly apart??

 

[2015ViperMTX]

What changed from the viper primary to the sidewinder?

 

[PowderFalcon]

What changed from the viper primary to the sidewinder?

If you compare the 2, it is quite noticeable. The apex/rx1 is much beefier. A simple comparison is looking at the spacers that go on either side of the fly weight. On the apex/rx1, they are paper thin. The sidewinder, at least 4-5 times thicker. This tells you how much more material there is on the apex/rx1 and how much more robust it is, esp with poor harmonics spinning weights around at 9000rpm. I'll mic them both tomorrow, but even visually it is quite alarming!

 

[Thunder Products]

how many stock clutches have you seen with problems?5-10?50?

Seen personally? 50+ with cracks or ones that have blown apart for people who wanted them rebuilt or replaced....or at dealers that we work with. I have a stack of sheaves in the corner and already have thrown a bunch away at recycling. My clutch and my business partner were pretty much the 1st ones that had cracks and actually had one come apart from 2 of the weight pockets while testing.....both sleds had under 1,000 miles. This was December of 2016 when I first contacted my local dealer and my contacts from Yamaha. We knew this clutch had strength taken out of it was not going to last. We both switched to previous style (Viper, Nytro, Apex, RX1) clutches and have zero issues now.

Heard or have seen issues from other people with social media or phone calls asking what they can do?? Well over 100+! I have a whole file folder full of pics with cracks and where they have come apart. And it doesn't matter what weight is in it or if it is stock or flashed.

 

[Thunder Products]

What changed from the viper primary to the sidewinder?

If you compare the 2, it is quite noticeable. The apex/rx1 is much beefier. A simple comparison is looking at the spacers that go on either side of the fly weight. On the apex/rx1, they are paper thin. The sidewinder, at least 4-5 times thicker. This tells you how much more material there is on the apex/rx1 and how much more robust it is, esp with poor harmonics spinning weights around at 9000rpm. I'll mic them both tomorrow, but even visually it is quite alarming!

The Sidewinder clutch had the webbing taken away that goes from the weight block pocket down to the sheave.
The Sidewinder clutch is very thin throughout the thickness of the sheave...I measured some sheaves at .094"
The Sidewinder clutch has the weight and roller location moved out so there is more force for belt squeeze. (Think of a 28" bicycle tire/rim with clothespins on the spokes close to the hub, compared to clothespins towards the outside or by the tire. The clothespins will have more force to move towards the tire.

 

[Thunder Products]

I have had 3 explode on me. Once came back threw brake caliper thru foot well and off my ankle. Somehow it didnt break it but was swollen and sore for several weeks and really had a bump there for about 4-5 months. Thunder products does your 911 cover help these issues any by making the towers more rigid? Have you had any with that cover fly apart??

Our 911 covers have helped with the strength of the clutch towers, but it won't help the cracking that is caused through the allen screw hole that holds the weight pin.

 

[yamamarc]

Our 911 covers have helped with the strength of the clutch towers, but it won't help the cracking that is caused through the allen screw hole that holds the weight pin.

I would be curious to see your 911 cover pared up with the hurricane harmonic dampening ring and see how that would work out

 

[SnowCatRider]

The problem with the clutches can't be blamed on 3 cylinder harmonics. AC made a turbo 4 stroke sled in the mid 2000's called the T660. This sled used the stock clutching at the time and lasted just fine. The engine was a turboed 3 cylinder suzuki engine borrowed from small Asian sports car. Those engines are still in sleds with tens of thousands of miles on them. I personally had one with over 13000 miles on it on stock clutching, and I had aftermarket turbo and tune work done on it so it was running tons more horsepower. Clutches never exploded, clutches wore as usual and the sleds are still around and one of the most dependable sleds ever made. I know it was my most dependable sled I ever had in over 20 years of sledding. Perhaps the 998 has some odd harmonics, or the shafts creates some, but I do not think it has to do with the 3 cylinders as a general rule. The t660 did not have a intermediate shaft and just went onto the clutch from the engine. Perhaps that is the issue?

 

[74Nitro]

The problem with the clutches can't be blamed on 3 cylinder harmonics. AC made a turbo 4 stroke sled in the mid 2000's called the T660. This sled used the stock clutching at the time and lasted just fine. The engine was a turboed 3 cylinder suzuki engine borrowed from small Asian sports car. Those engines are still in sleds with tens of thousands of miles on them. I personally had one with over 13000 miles on it on stock clutching, and I had aftermarket turbo and tune work done on it so it was running tons more horsepower. Clutches never exploded, clutches wore as usual and the sleds are still around and one of the most dependable sleds ever made. I know it was my most dependable sled I ever had in over 20 years of sledding. Perhaps the 998 has some odd harmonics, or the shafts creates some, but I do not think it has to do with the 3 cylinders as a general rule. The t660 did not have a intermediate shaft and just went onto the clutch from the engine. Perhaps that is the issue?

Those were low RPM engines (used in puny cars also if I remember correctly), with a heavy crankshaft making less than half the HP of a tuned Winder.
The Yamaha triple rocks but it does have some bad vibes, probably especially up over 9000 where some are maybe running.

 

[SnowCatRider]

Those were low RPM engines (used in puny cars also if I remember correctly), with a heavy crankshaft making less than half the HP of a tuned Winder.
The Yamaha triple rocks but it does have some bad vibes, probably especially up over 9000 where some are maybe running.

The t660 engine had a 8000 rpm redline and my sled made over 220 horsepower. Still no clutching issues.

 

[kviper]

A couple of my observations. 4 winders in my group. Two were belt blowers. The two belt blowers ended up breaking clutches. One through the weights and the other broke the spider. It's been suspected that belt blowing is driving the output ahaft bearing in. Is that creating some extreme harmonics having that bearing moved in? I would think so. I also feel that there is a lot of flex in the clutch. I did the Huricaine alignment and 911 cover on mine from day one. I felt if the cover can't flex the towers can't flex. I feel clutch flex puts extreme load through the weight pin mounts and of course the set screws would be the weak spot and it appears that's where the first cracks show up. I ended up going to a Tapp clutch. I just didn't want to take any chances of aluminum stuck in my leg.