Clutching on the cheap

[stingray719]

I'm simply stating the coil bind issue and how simply swapping to the 8dn belt solves that, to a certain extent, because as seen in a recent post^^ someone stated that after some miles they still had belt dust with the 8dn

Agreed. However we have not seen belt dust with 8dn, although we don't ride at high speed.

 

[stingray719]

Last year at one of the snowmobile shows. A Yamaha rep said the same thing. 8JP & 8DN are the same construction. Just a difference in length to accomodate
for the c to c difference.

Last season I tested both belts back to back multiple times on a mile long stretch of good hard pack snow on a lake near my house.
The 8DN did pull a couple of more mph. Engine rpms were pretty much the same for both belts.

However through out the season after I put some miles on the 8DN and the belt started to wear. I lost some rpms and I couldn't adjust the belt height
anymore because the adjusters were already maxed out.

The 8JP always worked good for me.

Somebody here I cannot remember who but whoever that was please chime in, tested both belts with a durometer and the rubber compound was different. At any rate at half the price and better performance I for one will not run the 8jp. In fact I have a brand new one on the shelf... Barry?

 

[Studroes144]

I actually got 2 so I'm all set. one is the original, the other a gift from a yammi rep for allowing my sled to be used for some testing. Would really like to hear more from larrypolaris and what his setup was!

 

[cannondale27]

My belt sizes I quoted are from yamahas chart there is a big tolerance. Chart is stickied in facts thread under drivetrain. I had no belt dust from 8dn in 1000mi. That is the standard the other belts have to meet or I will go back to 8 dn.

 

[larrypolaris]

Could you elaborate for us a bit on this? Some things we should all know to make a better judgement on your findings. Are you running a completely stock clutch setup or do you have aftermarket weights, springs, helix? What speeds were you reaching with the 8jp vs the 8dn? How many miles did you have on the 8jp belt and how many on the 8dn before you started getting the belt dust

Running Hauck VP weights and his helix's. His green secondary spring. Currently running a 45/39 helix.

I only ran stock clutching on the first weekend ride, ~200 miles. Then switched the clutching right after. Have 2900 miles on the sled now.

I've changed helix's a few time last year testing. Never saw eveidence of coil bind in the secondary.

Both belts when I tested them back to back were new and broke in with ~50 miles each on them.

Speeds on that day and snow, were 95-96 ish with the 8JP. 8DN was 98-99 ish.

 

[stingray719]

Running Hauck VP weights and his helix's. His green secondary spring. Currently running a 45/39 helix.

I only ran stock clutching on the first weekend ride, ~200 miles. Then switched the clutching right after. Have 2900 miles on the sled now.

I've changed helix's a few time last year testing. Never saw eveidence of coil bind in the secondary.

Both belts when I tested them back to back were new and broke in with ~50 miles each on them.

Speeds on that day and snow, were 95-96 ish with the 8JP. 8DN was 98-99 ish.

I believe Hauck Helix have room cut out in the spring cup to prevent spring bind if I am not mistaken. At least the one I have appears so (had it on a Phazer).

 

[Kerrdog569]

Got my secondary back from Ulmer's today and it's definitely better and now, I got the belt deflection where it should be,now I just need some snow

 

[Kerrdog569]

Before I buy a belt. I would have the dealer bring out 4 or 5 belts and I measure everyone before I buy the one with the correct length.
You would be surprised on belt length/width differences right from the factory. After market belts are even worst.

Correct belt length for it's c to c is key to any snowmobile clutch system.

It's amazing how an incorrect length belt can affect the performance of a sled.

If you have any performance problems with your sled. Be sure the belt is the correct length and width before you start changing any clutch parts.

Back in my grass drag days. We used to run different length belts and brands, and compare 60 ft times and et's.

The new belts are in stupid bags now,back in my racing days I used to go to my dealer and measure the belts and take the ones that were to my specs

 

[NOS-PRO]

Running Hauck VP weights and his helix's. His green secondary spring. Currently running a 45/39 helix.

I only ran stock clutching on the first weekend ride, ~200 miles. Then switched the clutching right after. Have 2900 miles on the sled now.

I've changed helix's a few time last year testing. Never saw eveidence of coil bind in the secondary.

Both belts when I tested them back to back were new and broke in with ~50 miles each on them.

Speeds on that day and snow, were 95-96 ish with the 8JP. 8DN was 98-99 ish.

The coil bind issue is with the Pink (stock) spring and white spring because the spring diameter is larger than other secondary springs. The green spring larrypolaris is running has clearance (Clarance)LOL.

 

[NOS-PRO]

The new belts are in stupid bags now,back in my racing days I used to go to my dealer and measure the belts and take the ones that were to my specs

You can still measure the belt with the bag Just pick out the largest with a caliper

 

[NOS-PRO]

You know I swear I read a Yamaha release (accurate or not?) stating that the new for Viper 8JP belt was supposed to be same as the 8DN only different length to accommodate the new C to C.

You are correct TD

 

[NOS-PRO]

Now, for you 8JP belt owners that want to sell your old belts or give your used belts to someone..... I have tried and tested these on my Nytro and the 8JP made the Nytro faster. (See my post in my XTX, setup, ride and review). Don't ask me why it worked....it just did and it was by accident. I grabbed the 8DN belt off of my son's Nytro to do testing and he wanted to ride around. I told him to take the washers out from the back of the clutch and just put the 8JP on so he could ride. He came back and told me that he saw 110 on the speedo. I didn't believe him so I took it for a ride. I saw 114 on the speedo (106 on gps). Like i said, stumbled upon something that worked. Is it the shorter belt with the little longer C-to-C that made it work? The engine compartment is full of belt residue....but it's working so I am leaving it.

Might want to get a hold of some Nytro guys if you have them lying around. All they have to do is take out the washers on the backside of the secondary clutch for correct belt tension. Just an idea.....

 

[Kerrdog569]

You can still measure the belt with the bag Just pick out the largest with a caliper

Yeah ya can but overall length is gonna be tough and that's what I really was measuring for in my racing days,the width was easy to adjust on my polaris and ski doo's,cat and yamaha need to get up to date on that,washers and shims come on man

 

[MorganKoda]

Now, for you 8JP belt owners that want to sell your old belts or give your used belts to someone..... I have tried and tested these on my Nytro and the 8JP made the Nytro faster. (See my post in my XTX, setup, ride and review). Don't ask me why it worked....it just did and it was by accident. I grabbed the 8DN belt off of my son's Nytro to do testing and he wanted to ride around. I told him to take the washers out from the back of the clutch and just put the 8JP on so he could ride. He came back and told me that he saw 110 on the speedo. I didn't believe him so I took it for a ride. I saw 114 on the speedo (106 on gps). Like i said, stumbled upon something that worked. Is it the shorter belt with the little longer C-to-C that made it work? The engine compartment is full of belt residue....but it's working so I am leaving it.

Might want to get a hold of some Nytro guys if you have them lying around. All they have to do is take out the washers on the backside of the secondary clutch for correct belt tension. Just an idea.....

I brought my XTX back from Ulmer's this weekend and I have two 8JPs taht I don't have a use for. The first one has about 1600 miles on it and the second is brand new, never put on the sled. I would definitely be happy to trade both of them for one 8DN if anyone is interested.

 

[Barney Maclean]

Hey Guy's
I don't meen to jump In! What are your opinions on the Hartman clutch kits? I got a quote of $500 shipped to my door to Ontario. Compete kits for both Primary and secondary set to my weight, riding style, sled, elevation etc. Spoke to Tom at Hartman and it sounded good o me?