Another belt blowing M8

DalensM8 · Feb 23, 2010

09 M8, stock primary and secondary springs, 42/36 helix. Last year I rode for a 1000 miles with no problem, lots of hard riding and never letting up on the throttle, sled ran great. I did blow one belt on a long hard pull, and I will say that was my fault. I was running for 20+ minutes, in really deep snow, very hard. This summer I took the sled to a dealer to gear to 54/66, since I got it back I installed the SLP pipekit. Sled runs strong with the pipekit, but I blow belts very quickly with WOT. Sled is well ventilated. I have blown four belts in 100 miles. Today I installed a 120/340 primary spring, running 73 gram weights between 0-4000 ft. Sled runs REALLY good, not overreving. Pulls real strong. The belts will go quick in the deep snow WOT, but seem to do OK elsewhere, and the pulls are nothing that the sled didn't handle the year before.

I plan on checking alignment. Should I have the 2010 front motor mount installed? Could this be a problem if the gearing was installed incorrectly, like higher gears installed instead of what was asked for? There was a mix-up at the dealer with the gearing and I assumed they got it right, but when I got the sled back it didn't feel snappy, like when you gear down, and I get some fast ground speed out of it when I am on hardpack. In the back of my mind I am thinking that the top end speed just seems too fast. I had a 46/38-34 helix and after gearing the sled just didn't want to pull RPM's anymore, so I went with the 42/36, and seems to be a lot better.

I will check gears, then align, then motor mounts if suggested

White Rad · Feb 23, 2010

wonder if they just didn't get your alignment back how it was after installing the new gears, maybe they left a shim off the dd input shaft or something. guess this is another reason to do my own work when re-gearing

DalensM8 · Feb 23, 2010

I definately need to have it checked, I blew two belts within ten miles, and I was honestly not riding it that hard. We found some little foothills with good snow and I had to get on it here and there, but nothing that the belt shouldn't handle. I did have a different clutch setup and thought that was the problem. I had a 160/310 primary, straight 36. I since switched to the 120/340 42/36 and stock orange in the secondary. This seems to help. I have noticed that the bottom half of the primary sheaves look polished smooth, not much in the way of black marks, a little on the top part of the primary, not much though. I will use fine sand paper and rough up the sheaves, wash the belt, break it in. How long should I break the belt in for, I am seeing for 50 miles and not over 50 mph?

Sled runs really really good, but just creates so much heat in the clutching, scalding hot clutches. Does anyone think with the primary sheaves being so polished smooth is creating any of this? Just doesn't seem right, frustrating. I have gone to all stock clutching and still same problems. All started after taking to dealer this summer. Dealer is great and I know they will help, but 6 hour drive away.

Thanks for advise and post on here.

shaneo11 · Feb 23, 2010

I have the 54/66 gearing in my 09 M8 with a 153" I also have the shift assist and rock rollers in my secondary. After a couple long pulls when I check my clutch temps my secondary is much cooler than my primary. Not sure if yours are this way or not. You might want to see which one is hotter of the two.

DalensM8 · Feb 23, 2010

They are both hot, but I would say the primary has been the hottest at times, to the point where it almost seems like the clutch outer plate is swelled. I know this sounds crazy, but taking off the plate the bolts don't want to come out of the clutch plate holes, and my friends right next to me, same clutch, showed me how it's supposed to be. I have the 09 M8 with the rock rollers and shift assist in the secondary. Last year the sled ran great, I would ride ride ride, deep powder, pull after pull, all stock, no pipe, and the sled ran great. I did blow one belt last winter on a long hard pull. Could this have caused issues in the crank, damage that is causing all of this?

wiley75 · Feb 23, 2010

What RPM does it pull at WOT?

DalensM8 · Feb 23, 2010

Around 8000, pretty much right where I need to be with the SLP pipekit, and like I said before, it runs really really good, but the WOT is where I'm getting the belt damage. I called a couple dealers, one said check clutch alignment, and check engine alignment. He said that they had a couple come in with engine out of alignment and the belt was walking out of the primary. Another dealer, the one I'm going to because that is the town I'm traveling to this weekend, said he thinks the clutch is out of alignment and possibly need reshimming in the secondary. I also said it may not be a bad idea to install the new 2010 front solid motor mounts, and they have also designed a engine torque system bolt for the M1000, and really helps. He did mention that maybe I should go back to stock gearing for the 09, because I had geared down to 54/66 (one tooth on both lower than what the 2010 M8 had geared to), since I put the SLP pipekit (which requires 8000-8100 rpm).

Bearcat · Feb 24, 2010

I have same issue with my sled too. Blowed two belts at wot. Ohterwise it runs really really good and even clutches are cool to touch. I'm going to replace the 48/40p helix with ac 44/40 and see what happens. Alignment may be off - haven't checked it. No belt blows anymore as I've drove < 100kmh

DonoBBD · Feb 24, 2010

Check your off set. You need 1.507 and have two .060 shims behind it for belt wear.

IF not you should get a set of hard mounts part number 0608-405 and press fit them in farther then needed to get 1.507 with two .060 shims behind it. About .125 or one eight inch more pressed in. You can then adjust your off set as needed and as the belt wears.

You can then run the XS soft belt and move the secondary in more for belt stretch. You cant run this belt with out moving the motor.

Don.

DalensM8 · Feb 24, 2010

Thanks for all the replies, appreciate it. It just doesn't make sense to me that it would run good one year, then to have these problems this year. I know I geared pretty low, and the SLP pipekit is supposed to bump the HP to 158, but this is almost the same as the 2010 M8, minus the lighter crank. Love the way the sled feels, runs smooth, engagement smooth, power smooth, but that WOT is what does it.

When I take it to the dealer I am bringing a list of things to check, and I will bring this post, along with others, so thanks for the recommendations.

DalensM8 · Feb 24, 2010

Dono,

I checked out one of your posts, I think in regards to a M1000, about the belt cupping on the outside. Today I called the dealer/mechanic that installed my gears. I told him what was going on and he asked if prior to the belt blowing if the belt cords would start to come out and on which side. I told him yes, and the cords would start to pull on the outside. Without hesitation he said its out of parallelism and that the motor would need to be moved, shimmed. He said what is happening is the belt is walking out of the primary. Stated that they have had a couple come through the shop like this. I hope this is it.

DalensM8 · Mar 1, 2010

Update !!!!

Well, I brought my 09 M8 into the dealer this morning. I told them the history of the sled, that it ran great last year, had a dealer install lower gears over the summer, then blowing four belts in 100 miles. First thing he checked, on his list of possible problems, was the alignment. It was off, and he was able to get it back into aligment by installing a .060 shim behind the secondary, on top of the one .030 shim already there. I ran the sled four a few miles, mainly high speed WOT across a lake (not the mountains in deep snow) and everything ran smooth, no excessive heat yet on the clutches. The real test will be in the mountains. I am also having them install the solid rubber motor mounts that are now standard on the 2010 M8's, and they are installing a front, right, motor mount to reduce the torquing of the motor. If the alignment was the issue, well it cost me four belts, some springs, and a trip 6 hours to a dealer, and the dealer cost. Hope that was the problem, we will see and I will post an update.

snowblind · Mar 2, 2010

if you didnt do the gears it would have been ok.

DalensM8 · Mar 2, 2010

I hear you. But where I ride, mainly in the steep, and usually deep, it's the way to go. Lower gearing will reduce clutch heat and be more efficient in the mountains. But like you said, seems like that is where all the problems started, and I hope that is where it ends. Will post an update as to whether that was the problem, maybe there is more to it. I am hoping that the clutches being that far out of alignment caused all the excessive heat issues, any thoughts on that?

DonoBBD · Mar 2, 2010

DalensM8 said:
Dono,

I checked out one of your posts, I think in regards to a M1000, about the belt cupping on the outside. Today I called the dealer/mechanic that installed my gears. I told him what was going on and he asked if prior to the belt blowing if the belt cords would start to come out and on which side. I told him yes, and the cords would start to pull on the outside. Without hesitation he said its out of parallelism and that the motor would need to be moved, shimmed. He said what is happening is the belt is walking out of the primary. Stated that they have had a couple come through the shop like this. I hope this is it.

See this is the problem. You can get the DDrive sled to out run the chain sled on ice but you plop her on snow and extra load and you smoke the belt. The belt load thins the belt and then the belt under load is slipping. See this over and over in all the DDrive sleds. RUBBER BAND EFFECT

If you guys take the time to do some math on the off set you will see that the cat bar is to set thing up 1-1. If you drop gear or find heavy load you will need to move the fixed sheaves together more for the extra load you put on the belt. Lower gear will up shift more getting into the extra load area where you need the fixed sheaves closer together.

I guaranty every one of you guys have seen this in spring heavy snow conditions because there is not enough room to move the secondary in enough to take the heat out of the clutch.

When you have a guy blow by you with another cat he is the guy that moved the motor over.

Don.

EDIT: DalensM8 you need to watch that belt heat now that you moved it out. I bet when you get that sled in the deep the belt will heat up fast. Be ready to take those shims added out. You are headed in the right direction with the stiff mounts and motor stop. The real way to fly is move the motor.

DalensM8 · Mar 4, 2010

Update on Post!!!

Well, made a run on the hill today, pretty good snow, some hardpack and some powder, some flats, and definately some very steep, about 20 mile in all. This is first run after sled was taken to dealer and the clutches re-aligned, they had to put .030 and a .060 shim in the secondary (moving it to the left) for the re-alignment, but I see on the work order that I was also charged for a .090 shim. I will have to pull the secondary off and see how many shims they put in, but I was there and witnessed the simple re-alignment procedure and it was re-aligned using the 09 bar, I think 1.65. They also checked the parallelism and that was good. Anyway, pull after pull after pull, WOT, WOT, WOT, no fraying on the belt, no marks on the primary or secondary, and is running smooth. Believe me, I checked and checked, paranoid about blowing another belt. Seems like the problem was taken care of. Prior to this, I could almost blow the belt on command, and today I could not, the belt looks good, no slipping, etc. Clutching still warm, but I can hold my hand on the outside of both clutches, where before I could not even touch the primary anywhere, scalding hot, but not today. Frustrating, as a simple alignment check could have saved me four belts.

DalensM8 · Mar 8, 2010

Last Update!!!

We ended up getting 42" of new snow, wet snow, so a very tough go on the sleds and belts. Today I put on about 40 miles, mainly long hard pulls in deep deep snow. No fraying, no issues with belts. Two weeks ago when I was pulling my hair out with the belt issues, we used a heat gun to check sheave temps, and belt temps. We were seeing 200 degrees on my belt. Today, after some really long pulls, heat temp of about 105. Looks like a simple clutch alignment was the problem. I am actually thankful that this was the problem. It would have been tougher if I had gone somewhere and they couldn't find the problem, but thankfully this was an easy fix, wish I had a clutch alignment bar a few months ago, or that the dealer had checked before sending my sled along. Thanks for help and suggestions.

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