I've read all searched threads on Dayco Belts here and have not found anything matching my problem. SO.....

The Problem: Riding this weekend my Dayco 2018 failed, blew cogs and set off the belt engine seizure. Upon taking it out I discover about 1/3 of the cogs missing and found cracks in the cogs that are still there. I noticed some light clunking at idle, and after driving approx. 15miles it blew.
Please See photos on my photo page near the bottom. http://photos.yahoo.com/yamihoo2 http://photos.yahoo.com/yamihoo2

The Facts: I installed the Dayco simply out of curiosity of performance change, since I wanted to have a spare laying around anyway given my 20 years of snowmobiling experience. My stocker had 900mi. on it and was seemingly functioning fine. I did lose 3mph top speed with this belt, otherwise did not notice any performance change. It did not squeal or slip at all. When I pulled out the stock I measured width straight up with a caliper (not with this "smoke and mirrors" method of using two straight edges and a caliper). I didn't write down the numbers but I remember the Dayco was .010" wider using this method an the widths were in spec. I believe the caliper right on the edges is an accurate comparison method to measure unless the V angle is actually different between the two. Anybody disagree? And if the V angle doesn't match, then we have a problem here. Since I consider .010" not worthy of shimming I didnt.

Probably most important to the members here, yes I did check tension and found it within spec. again, unfortunately I did not write the number down, but it was within spec.
I ride mostly trails with sand, gravel, mud and some hills. I do some mud and water riding as you can see from my photo album, but only 10% maybe, but I believe I never got the Dayco wet.
Perhaps most important lately I've been doing some hard pulling. Very hard pulling, pulling 12" Dia Oak logs about 10-12ft long. I imagine these logs weigh some 800 or more lbs. But at no point did I ever smell my belt overheating or burning.
My clutch sheaves appear fine with no noticeable damage or grooves.

I'm open to questions, but please NO MOD QUESTIONS! You can see my mods on my profile.

My theorys:
I overheated the belt pulling too much weight.
I incorrectly observed tension spec. and should have shimmed. I did not use specified weight for tension measuring, but believe I did a good job estimating. (I work in engineering)

My opinion:
This belt tension/shimming thing is blown out of proportion and hyped up way too much. I've rode snowmobiles for over 20 years putting really bad belts, wrong size belts etc. on an did rarely ever experience this especially with a new belt. FYI- there is no such thing as clutch shimming that i"m aware of on a snowmobile or a Polaris ATV..WHY on the Prairie???

My questions:
Is this belt made specifically for the Prairie or was it just cross referenced?
What do you think happened?
Has this happened to anybody else?
Why is this belt tension such a big issure with these machines, when snowmobiles have used this drive design for many years and no shimming and adjustments are needed for them?

 

Nevermind the link in the thread, just click on the regular photo page icon on the left. Thanks!

 

What is big and green and goes whap, whap, whap, whap?

Yamihoo's Prairie.

Sorry, I had to do it.

 

I witnessed this happen. After yamihoo heard a slight clunking, I took it for a little ride. All of a sudden it just let go and tripped the belt reset. When we took it apart there were cogs laying all over the place and like his description there were cracks/tears between all of the cogs that were still on the belt. If it overheated I would think you would smell the belt cooking. I had a polaris and when the belt was getting bad, you could easily smell and hear it slip. I was also looking at the Dayco for a cheap factory belt alternative.

 

I have had this happen w/ a fairly new (less than 300 miles) Kawasaki brand P650 belt. I have had a P700 belt on my quad for over 1000 miles and it is still fine. I will probably pull a shim out before my next ride as it is at the loose end of specs. I do not know why my last belt let go. I was doing some top end runs and had been running at 67-68 mph for a good mile. I then came up a long hill and backed off coming around a corner. Was down to around 45 mph when the belt let go. Fortunately, I was withing 100 yards of home and drover her the rest of the way home. What a pain cutting out all the pieces of shredded belt that wound into the clutches. Fortunately, it appears to have been a one time problem.

 

Update: I did pull my OEM belt out at about 900mi. before I tried the Dayco2018. I'm looking at it now and it also has cracks in the inside cogs, very small but visible cracks. Also I've done some more measurements, comparing the two belts and two measuring methods.

First the Kawasaki measuring method using two straight edges on the V angle and measuring across the top surface of the belt with a caliper.

OEM after 900mi. 1.138" wide
Dayco2018 after 200mi. and failure = 1.090"
=.048" difference

Second using caliper right on edges of belt

OEM after 900mi. 1.093"
Dayco after 200mi. 1.062"
=.031" difference

Error between two measuring methods .017"'