why am I busting so many belts?? :@

venture700

venture700

New member
Joined
Nov 8, 2006
Messages
202
Age
36
Location
makkovik, labrador
Im sick of busting belts on my 03 MM 700. I tryed everything such as lining the secondary up with the primary clutch using a clutch alignment tool from royal distributing, different clutch set-ups, more/less twist on the secondary. I ill blow a belt in a matter of hours if im hill climbing. when I buy a new belt I washes it with soap and clean it all up then takes it easy for the first tank of gas. there is only one more thing i can think of and thats my jackshaft is slightly bent. when i put my machine in neutral (i have neutral because i removed my reverse gears) the secondary clutch wobbles from side to side a little. also every single time i do bust a belt the first thing that happens is the line will start comming out of the sides of the belt and next is the whole top of the belt comes off. it rarely busts completely. Im really sick of ordering a new genuine yamaha 8dn belt ever week there over $100. hopefully one of you guys on here had this problem and solved it. thanks guys!
 
Id start with getting a new jack shaft. That seems to be the only logical thing that it could be adding twist to the belt along with the torque from the motor.
 
If the engine mounts are good and clutch runs true, then (X2!) buy a new jack shaft.
 
Check the jackshaft bearing behind the secondary.They do wear out and ruin the jackshaft when they do.Grab the secondary clutch with the belt off and see if you can push it back and forth or up and down.Next grab the pri clutch and see if you can rock the moter.Any play in these will cause problems.
 
my motor is solid. all the mounts are like new... I forgot to say this sled has 25,000 km on it and the only bearing I never changed before was the jackshaft bearing next to the secondary (i put new bearings on the whole suspention, chain case and drive axle every fall but kept putting off the jackshaft because i never heard of one going on that type of sled before). there was never any loud noise comming from that area and the secondary is solid but I done a search and found out if the bearing goes bad the shaft will bend so it looks like ill be getting a new jackshaft and bearing tomorrow. HOPFULLY this solves my belt problems! how long/ how many km's do you guys get out of a belt on average driving full throtle most of the time?? I know I average 100-400 km on a new belt and thats not normal
 
how hot does you primary and secondary get when climbing. I'd bet you are over heating them
 
I can get 2 years out of a belt but dont ride in deep powder.The clutching could be off.Are the shieves hot to the touch after you blow a belt.You could be slipping and that will do it as well. You could be right about the jackshaft being bent but i have never seen it.The bearing goes dry than seizes ripping the lock screws around the shaft macking the new bearing immpossable to lock dowm and sit tight.

Hope you get it fixed WINTERS HERE.
 
maxdlx-my clutches do get pretty hot climbing/ boondocking with my stock clutching and that caused 3 cracked movable sheaves revving 9000 all day) so i asked turk how to cool them and get my rpm down to 8400. but with that set up he told me by adding weight and getting a weaker rate spring but that made my machine loose ALOT of power. no acceleration at all so i bought a 04 viper mtn clutch (stock) this summer and have not tryed it yet but i know its not the heat caused it.
glid-my cluch had no overdrive
ill get that jackshaft and bearing and hopefully also that viper clutch causes my problem
 
od

The helix is machined to allow the secondary to open more, sheaves are the same. My friend machined his for more top end and the belts at full shiftout would come off the primary. Pulled the strings out of the side of the belt in 20 kilos
 
Had the same problem with a 97 700MM. I finally figured out that snow was getting in around the top of the front shock mount, silicon fixxed my belt problems. I always try to start with the cheapest repairs when chasing gremlins.
 
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