Well, ill start from last year.........In the middle of the season last year I blew my first belt on my 2002 MXz 700. I couldent have had any more than 900 miles on that belt which seemed kind of low to me considering on my old sled I replaced my first belt after 1500 miles. I thoght nothing of it and changed the belt and kept on riding. After about another 250 miles maybe less I blew another belt, the thread comes out first and than the top of the belt starts peeling off. I managed to get it back to the trailer and decided to bring it to my dealer the next day and they discovered that the clutch alighnment was off by an 1/8th of an inch and that was why I was blowing belts. So I than had to buy two more belts, one for the sled and the other for a spare which can get expensive! Since than I have put another 400 miles on my sled and now I am into this year with it and it started to happen again! This year I have milled my head .010 and put boyesen reeds and spacers in it and my max RPM is 8100 on my tach is this too high? I was going thru a field with the wick to the bar and heard a weird soft high pitch noise and let off right away, but kept on riding(thoght I was hearing things). It did the same thing again but only maxed out and I decided to stop and check it out. The threads on the sides of the belt were starting to come undone, but I was able to finish my ride with out the belt starting to peel off from the top. There was no clunking noise and I didn't hear the soft high pitch noise again because I took it easy so I could make it home. I am debating on getting a tool to alighn the clutch myself instead of bringing it back to the dealer but I have no clue on how it works, do I have to unbolt the motor and retorque it? Should I get torque bars so the motor doesn't move around as much? Am I running to high rpm wise? Can someone please help me on this, I am sorry for the long post and I thank you guys and gals ahead of time! Oh one more question, is it normal for these sleds clutches to get out of alighnemt so often? I have an EPI trail clutch kit on its way and now I am scared to instal it because of this.

I would check alignment etc.....but these sleds are harder than average on belts if ridden hard, in the newest models they have the newest version of the TRA clutch and use a new wider belt which supposedly helps with belt durability issues......this is and has been a weak point on doo's for a while.

Anyone else before I order the sled pro alighnment tool and torque bars? I know a lot of people on here have the knowledge.

First thing you need to establish is whether everything in the engine / drive-train is staying in alignment under severe load:

1) Check engine mounts for hardness ( a good tell-tail of soft mounts is exhaust ball joint wear and leaks in the seal)
2) Check alignment with an OEM bombardier gauge which already compensates for the offset
3) clean all sheeves with hot soapy water to pull any contaminants out of the surfaces then clean them with 600 grit emery or 000 steel wool.
4) Check your track tension and hyfax condition, the common denominator when you have repeated high speed belt failure is parasitic drag down stream of the pulleys (remember as speed / RPM increases, drag multiplies also).
5) After a good belt break in of about 25 miles varying throttle rates never more than 2/3rds do a short run, stop the observe primary and secondary pulley temperatures (heat is usually the cause of belt delamination).
6) Take Notes !!! The only way to diagnose drive-train efficiencies is to have hard facts to compare with :thumbsup:

I put a torque rod on mine a doubled if not tripled my belt life. All Doo needs to do is put on heavier durometer motor mounts to help with engine twist.
Proper belt alignment and offset is critical, the rod helps greatly in keeping it that way.
There are many other things to consider as mention in above posts. If your clutches are to hot to touch for over 5 seconds this will break down the glue's that hold them together and blow. I'am a big believer in big spring poundages in both clutches and LOTS of pin weight.

Guess I'm a non conformist when it comes to this subject. My advice is to throw doos specs and most the alignment bars out the window. On the zx sleds I push the engine clear forward in the mounts (the belts are too long for the factory spec).
I line the clutches up using the old 3/8 flat bar method, and I do not allow for twisting, line em up straight and set the torque stop snug (not tight) to the motor. Use the belt width plus .5mm for the offset spec. Set the deflection so it trys to creep the track. Use the jap made 127 belt unless topspeed is your only concern.
Back in the real bad belt blowing days ,summits and those frickin 067's, I used to carry a tube of superglue and some small surgical scissors. I'd have the hood open several times a day looking for those loose cords. Snipped em flush and secured the ends with superglue. It actually saved quite few belts, at least for the rest of the day anyway. We tried everything, gearing, clutching, alignment, gates dayco,doo , you name it. We started filing out the motor mounts and using yamaha belts, this and gearing down was the best you could do. Doo must have been paying attention, because they came out with the 127 belt, just a shorter version of the yam belt.

Hello, thank you for you replys. I know these sleds can be hard on belts, but I figured I should be getting more than 400 miles out of them? When I stoped and checked the belt I did happen to check the temp. of the clutches with my hand and they did not seem too hott. I have broken in all my belts properly and the hyfax seems to be in good condition along with track adjustment. I do need to check the motor mounts to see how solid they are along with cleaning the clutches. What exactly are the sheeves, is that where the belt rides which looks like the inside plates?(no clue about clutches im trying to learn). Do I need to take clutches apart to clean them? I think I will try what mikadoo is telling me first and than try what Hillpounder is saying. Thank you for your help so far I hope to solve this problem. Does anyone know about how much an OEM alighnment tool is and if i can get it right at the dealer?

Well my experience has been good with doo belts. I use Crankshops alignment tool and it has worked great for me and it is easy to use.

Both my 670H.O. (067 belt) and my 800 (127 belt) go for 2000+ miles before showing signs of wear.

Saw 117mph on my 800 last year several times. Works for me!

How often do you alighn your clutches pete? When u do it are they out of spec at all?

Olympic2002,

If you can get a 3/8" sq. steel bar, (nice and straight) about 19" lg. you can set alignment.

Open the secondary and drop the bar in, let it close back up and pinch the bar. Roll the secondary down until the bar touches the top of the primary clutches center spindle. measure from the backside of the 3/8" bar ( closest to center of primary) to backside of clutch sheave( yes these are the faces were the belt rides).

The distance should be about 1.400. Measure the front of primary sheave and the back. make them the same dim. Doo wants you to put a small lead on the front dim, by about .060 to allow for engine twist but if you set the rubber stopper very snug this shouldn't be an issue.

There is also a center to center dim. to set. This about .650. Distance between the two clutches in the middle.

So ther are 2 major dim. that need to be set and the crankshop tool allows both to be set all at the same time.

Hope this helps some

Good luck

I check the alignment once a season, and they almost always are right there.

When delivered from my dealer, they were out quite a bit.

everything is covered already, but what fixed it for me were two new clutch side motor mounts(they are cheap). follow that with motor allignment and a fresh secondary cleaning-greasing.the torque rod sounds like a good idea...my motor was not as large and torquey as yours, so i could get by with the factory rod.

pardon my ignorance, but where does a guy get his hands on a 3/8 19" piece of bar?

You can usually pick up a piece from a welding/fabricating shop, or scrap metal yard, Russ.

WWW.metalmart.com