Clutches and Blown Belts

[BryKlu]

Hey everyone!

I am in the process of attempting to fix a belt blowing issue which has happened after high speed rail grade runs and just yesterday in a foot or two of powder. The clutches are hot to touch right as I open the cover to change the belt in 5 degree weather. It looks like my belt is sitting over 2mm below the top of the sheave so I'm going to add washers to the back. I am going to clean the clutches entirely while I am in here and check the belt deflection. I have a few questions and have posted a link below to some photos that may aid this inquiry.

https://photos.app.goo.gl/vnE5ZKaiky1Xgnum2

1. Are those my tip weights in pic 1 and 2, and do they look messed up? Looks like they have a huge carved channel in them. Is this normal?

2. I don't feel dishing on the sheave faces and still need to sand them but do they look ok?

3. What type of grease is the red stuff where the secondary mates to the driveshaft? Will high temp brake and wheel bearing grease work that is a "multi-purpose" lithium complex?

4. I see Yamaha lists 0.5mm and 1mm washers for adjusting the belt. I am planning on getting appropriate ones from the hardware store. Does a 1m washer raise the belt 1mm respectively? Not sure if the math quite works like that. My new OEM Yamaha belt is sitting 2.35mm below the top of the sheave if I measure to the bottom of the rib where the meat of the belt starts. If I am measuring correctly (the service manual isn't that specific), then I believe this could definitely be the root of my issue.

Thanks in advance for any information! This forum has been essential to a successful season with my first sled. I did feel like I needed an Apex or Sidewinder in the foot of snow dumped on Price County, WI Monday. Trails were untouched

 

[NOS-PRO]

Those are your secondary buttons that your helix rides on in pic 1,2....and yes, they are pretty much toast. Like brake pads, they wear. Easily replaceable...just like pulling a tooth, pliers works awesome. Tap new ones in with rubber hammer.

Your sheaves look ok, don't sand them....if anything, take a fine scotchbrite.

Any grease will work, just don't go crazy so the stuff flies out and gets on your belt.

If you add a washer to the (3) 8mm bolts on the rear side of the secondary, it will pull your secondary sheaves together more and make your belt ride higher in the secondary. Taking 1 of the washers out will drop your belt in the secondary. You want to be close to the top of your secondary, but not over your secondary sheaves too much.

 

[BryKlu]

Those are your secondary buttons that your helix rides on in pic 1,2....and yes, they are pretty much toast. Like brake pads, they wear. Easily replaceable...just like pulling a tooth, pliers works awesome. Tap new ones in with rubber hammer.

Your sheaves look ok, don't sand them....if anything, take a fine scotchbrite.

Any grease will work, just don't go crazy so the stuff flies out and gets on your belt.

If you add a washer to the (3) 8mm bolts on the rear side of the secondary, it will pull your secondary sheaves together more and make your belt ride higher in the secondary. Taking 1 of the washers out will drop your belt in the secondary. You want to be close to the top of your secondary, but not over your secondary sheaves too much.

So do you want any of the ribs touching the sheaves? Is the measurement in the manual to the top of the belt ridges or the bottom of the ridges? Ok new ramps ordered. Checking deflection too.

 

[BryKlu]

Redacted

 

[BryKlu]

Offset is only 12.79 between primary and secondary. Going to add a 2mm washer.

Secondary spring is 2.5mm short--72.5mm instead of 75mm. Ordered a new one. Hoping these two changes along with replacing the buttons will fix any issues

 

[NOS-PRO]

So do you want any of the ribs touching the sheaves? Is the measurement in the manual to the top of the belt ridges or the bottom of the ridges? Ok new ramps ordered. Checking deflection too.

Top ribs of the belt should be close to flush, but just down a little bit in the secondary. If you put the ribs above the secondary, you have a chance for the belt to delaminate the top rib surface.

Ramps, belt deflection, clutch offset and secondary buttons will cure a lot of your problems.

 

[BryKlu]

Top ribs of the belt should be close to flush, but just down a little bit in the secondary. If you put the ribs above the secondary, you have a chance for the belt to delaminate the top rib surface.

Ramps, belt deflection, clutch offset and secondary buttons will cure a lot of your problems.

Great. Deflection seems fine then as does the sheave to sheave gap which is 35.05mm. I rode through the storm that hit Wisconsin then the 2 days following so the belt had to work hard in the powder especially on the turtle flambeau flowage which is basically a high speed powder run. Thanks for all the replies! Hope this can help a future searcher someday.

 

[Vectornut]

Dont replace the washers especially with hardware store washers. Just replace the three bolts that hold the washers on the back side of the driven. Also, use the original washers that are there as they dont wear out. Just the bolts wear out. Replace also the 3 pucks. Then check the deflection and go from there.

 

[BryKlu]

Dont replace the washers especially with hardware store washers. Just replace the three bolts that hold the washers on the back side of the driven. Also, use the original washers that are there as they dont wear out. Just the bolts wear out. Replace also the 3 pucks. Then check the deflection and go from there.

Those bolts look fine but I ordered new ones. The deflection is good. I need a 2mm shim/washer behind the secondary on the driveshaft being the offset is only 12.79 and not at least 14mm like the service manual says.

 

[thrasher]

The ramp buttons from Yamaha are garbage and are 10 x more expensive than the aftermarket ones from Royal Distributing. Not sure where in the U.S. that you can buy them, but someone on site can hopefully make a suggestion.

 

[BryKlu]

The ramp buttons from Yamaha are garbage and are 10 x more expensive than the aftermarket ones from Royal Distributing. Not sure where in the U.S. that you can buy them, but someone on site can hopefully make a suggestion.

Ugh they are 1.99! RD part 03-151-090 for all models 94-2017 except some they list. Maybe I'll order and return the others unless we get hit by more snow and I get antsy

 

[thrasher]

Ridiculous Yamaha pricing. Buttons didn't last a season of 3000 miles and cost me over $50(almost puked when he told me the price). Aftermarket ones lasted me 2 seasons, about 6000 miles and cost $6.

 

[BryKlu]

Ridiculous Yamaha pricing. Buttons didn't last a season of 3000 miles and cost me over $50(almost puked when he told me the price). Aftermarket ones lasted me 2 seasons, about 6000 miles and cost $6.

Mine are original and the sled now has 7600. According to the wear limit specifications in the manual, I could actually still use these ones as the minimum measurement is only 2mm, but at $1.99 a piece there is no reason to not replace them seasonally. I will definitely be doing so from now on. I'm having to learn all this stuff first-hand since this is my first snowmobile but I can't complain with 2500 miles for the season so far...

 

[4strokeluvr111]

I installed 3 ea., 2" soffit vents in the top clutch guard to help get cool air into the area.

FWIW - I can't see the pics.

Has you primary been gone through?

 

[shed]

i have not replaced the secondary buttons on my 07....yet....yes they are getting close
3 of the 4 belts have blown on top end runs, 95-102mph
the 4th, i was doing 60 on a road.
all had near 5,000 miles on them, so not the sleds fault
this last belt has almost 1,000 on it
sled just turned 20,154 miles on the weekend
i have new buttons, just waiting for the old ones to get to 50%
blew the drive clutch 2 years ago, a tower let go
i am still using that belt...yippee

thanks barn of parts for the clutch and bulkhead repair kit
you rock