Blowing belts

[Snowaddict]

My father sold his '03 Rx1 to a friend this year. It had 2800 miles on the original belt. Well, the belt didn't last much longer after the guy bought it and blew. I figured it was just time. He gets another belt and it doesn't last 100 miles. Now just yesterday he blew his 3rd one (600 miles later.) I saw it for myself yesterday and have never seen a belt go like that. What a mess, shredded, and strands wedged everywhere. He states everytime it has happened it was wide open on a lake and looked exactly like it did then. Here are some of our theories: 1)clutch alignment is off (if there is such a thing) or 2) the first one died of natural causes, but after cutting out the strands from it with a knife, it scratched the secondary and left some small burrs (which when the secondary is completely open lets the belt go down far enough to rub against these. Anyone have thoughts or experience similar problems? My father never had one problem with this sled. I have not blown a belt on my '05 (I try the preventive method, though and change it at the beginning of each season.)

 

[AaronBND]

I would be curious to know if he pulled the secondary after he bought it from your dad. It could be the alignment. Don't think it would be the little scratches. They are pretty tough. Changing the belt every fall is the way to go like you said! Good luck and let us know.

Aaron

 

[impalapower]

Did he put the belt on in the correct direction? A guy on one of our rides put a different belt on and within 20 miles it was no good. He forgot about the direction and didn't check. Put on another new belt in the correct direction, it was fine.

 

[Snowaddict]

belt

I'm pretty sure he did not do anything with the sled, other than adjust the suspension a little. I forgot about the direction thing myself and didn't even ask him about that. I'll have to check with him. If I'm remembering correctly the arrows need to point to the primary? (I'm assuming this allows you to read the numbers and letters correctly, otherwise they'd be upside down?)

 

[zelinsmrx1]

Not too sure what causes this. I have an '03 and last season I couldn't seem to get more than a few hundred miles on one. This year I bought some more belts and I got about 1400 miles on one and so far 450 on the next one. I think the one with 1400 miles on it failed due to the issue with the secondary on my sled (see my post). Maybe there are old stock out there or bad batches. I don't understand why I was blowing belts last year and now they are lasting and I didn't do anything other than check the alignment last year and it was ok.

I try to make sure I break my belts in and it seems to help them last a little longer. I keep it under 65mph or so for the first 30-40 miles with no hard accelerations.

 

[Yamanator]

Make sure he did not twist the secondary spring to tight and started making grooves in the sheave's, This is what Hackers in Michigan told me I did to mine and they had to replace them after I was blowing belts, I had to fight with Yami to get them to cover just the primary sheave's and help out with the secondary one's also. I do have a Y.E.S. warranty and they did end up helping out a little more. My total cost out the door with all new clutch's and new belt was $300.00, but now the sled won't pull 10,000.00 RPM. I am hoping to get back up there tomorrow and fix that. All they did was go back to the pink spring in the secondary at 60 degree's and I had the white one in there at 70. They said this is what could have made those really bad grooves in the sheave's..................... Yeah right with only 3900 miles on it and the white spring just went in at the end of last year.

 

[LazyBastard]

It'll groove even when all stock. Its overgeared and has a hard time engaging.

 

[Yamanator]

It'll groove even when all stock. Its overgeared and has a hard time engaging.

Lazy, I have a all stock primary with just a little weight added (I don't know where because my buddy set it up) and I now have a all stock secondary with the pink spring at 60 deg. I was told by another member on here to twist up the secondary alot more to get better top end, what do you recommend ? I live on a lake and do alot of long runs on there, the sled would hit at just over 10,000 and pull to 10,500 before I took it to the dealer, and now it does not come close to that. I have an exhaust and filters and thats about it, can you give me a good setup with the stock stuff ? I have 144 studs in a 1 inch camo track and I weigh in at 250 pounds ready to ride.

Thanks for any input.

 

[LazyBastard]

Twisting the crap out of the secondary is NOT the way to gain top end. It might help you with holeshot, but it will actually HURT top end. What you want to do to bring RPMs back up is REMOVE WEIGHT from the primary, or switch to a harder primary spring.

Now I can give you my own personal experience with this. My second sled is OLD. 87 Exciter. When it was all stock, it would bog bad out of the hole and underrev at the top end. End of 1/4 mile, a stock 98Vmax600 would take me by ~150 feet. First thing I did to it (this is before I knew what I was doing) is I twisted the crap out of the secondary. This gave me most of the holeshot I was looking for and brought my RPMs up to where they should be (7300 on that sled). Now that Vmax was only getting me by about 50 feet. Then later on (two years ago, when I finally *did* know what I was doing), I put the secondary back to stock, ground down the primary weights, and stuck in a 3/8" shim behind the spring. This finally woke that sled right up. Zero hesitation off the line, and holding a real good top end. It now will nudge 100 mph on the gun (I don't think it even did 90 before, the Vmax peaks at 92) and knocks the socks off that vmax by about 250-300 feet.

Now being a 2-stroke, it is a LOT more sensitive than your RX, so don't expect your results to be that drastic. Also, I think that part of the problem was that that sled was just plain screwed up right from when I got it. I really dont know the history of it from before I bought it at an auction.


Basic rule goes like this;
Change RPM: adjust the primary.
Change backshift characteristics: adjust the secondary.

 

[Yamanator]

Thanks Lazy.

 

[Thatspec]

Belts need to be broken in, or so the theory goes. Our sheeves have different angles on each side, and they do not initially match the belt angle.

I recently blew up a brand new Ultimax 3 in 80 miles. It appears they are warrantying it (cashed my $6 check at least). I went down to 60 degrees on the secondary to break in the next Ultimax 3, and didn't do any boondocking or deep powder for probably 6 hours use. Put the secondary back to 70 degrees and it has been going strong for 1000+ miles of 5-40mph climbing in deep snow. Lots of dis, and re-engageing. Sometimes I'll stop and and rest it and its too hot to touch.

Wash it with soap and water every few rides. Clean the sheaves with acetone, or similar. Scuff up the sides of the belt with 120 grit occassionally. (this is all stuff Tom Hartman told me to do).

I keep an OEM belt as a spare, they are virtually indestructable but prefer not to use it.

Hope this helps, Mark

 

[ReX]

I recently changed the belt on my RX-1. It had well over 8000 kms (5000 miles) on it.

The fiber on one side was just starting to fray and stick out a little in one spot so I figured it was time...

Last season the second belt lasted about 5000 kms (3000 miles) until a PTO leak spattered it with oil and the next one I changed at 5000 kms just to have a new belt this season.

Your belts should be lasting much, much longer.

I would definitely check the alignment, both offset and center distance. It's probably not a bad idea to check parallelism too.

I also do break my belts in for at least 10-15 miles before any WOT (even short bursts) and a good 40 miles before any long high speed runs.

I often clean the belt when first installed, but that's it. After that I just check things over after each ride.

 

[HAMMER]

Wash it with soap and water every few rides. Clean the sheaves with acetone, or similar. Scuff up the sides of the belt with 120 grit occasionally. (this is all stuff Tom Hartman told me to do)

Just wanted to add to this:

We abuse clutches & belts in the mountains so trail riding you can extend the cleaning to intervals to a visual inspection every ride or two, compressed air clean every ride or two, and hot soapy water as necessary.

When cleaning the surfaces of contaminants/debris it should only be done to the appropriate levels.

Lightest = Acetone or Brakleen (no-residue)

3M Scotch-Bright
7445 Light-Duty White
7448 Ultra-Fine Gray
7447 General-Purpose Maroon

Last Resort = Fine 3M emery paper for a really boogerd up sheave (blown belt, grooved, nicked, etc...)

(Note: Steel Wool is not recommended because the steel fibers can wedge in between the bushings and shafts. This may/can/will bind the moveable sheaves on the shaft)

The goal is NOT to remove the clutch surface but to remove unwanted contaminants/debris from the surfaces. Only apply enough pressure to the material being used to do so.

Center-to-Center (owners manual)
Offset (owners manual)
Deflection (belt widths will vary check each time)
Proper Setup (weight-spring-helix)
Clean New Belt (removes drum release silicone)
Break In New Belt (conforms to the sheaves for more surface contact)

 

[Snowaddict]

good info.

Thanks for all of the good info. I'll have to print this out and give it to him. I'll also have to keep it in mind for myself. I do know even a scuffing/cleaning every so often seems to help performance a tad (unless it's all just in my head and I'm trying to justify doing it