HEY CLUTCH GURUS-Need help-- diagnosing violent belt "bounce" (erratic belt movement)

[Murph]

yeah, kind of weird on the pro, but just a fyi, I did install the slp torque arm right off the bat, and stiffer motor mounts...figure my mod sled has motor pretty much bolted in solid and makes 204 n/a legit hp with 3" track, never has it blown a belt...

I really wonder if the soft moveable mounts are a big part of the problem on the pro.????
Oh, if anybodys wondering I took the stock rubber mounts and filled the "gaps" with liquid rubber to firm them up.

If guys are seeing the turbo airbox bolts hit the bulkhead thats 3/8 or more inch away, thats motors moving a HUGE amount in a sled with no torque arm, and this would put massive side load on the belt.

I go back and forth on the motor mounts. My 2011 ate belts once the original mounts were smoked. I think about firming up the motor mounts and or torque arms but I wonder what the increased stiffness will do to the cases or crank?
I'm not concerned with my "comfort" or vibration isolation that the stock rubbers provide....

 

[pura vida]

there is not magic bullet for the clutching to keep the belts cool. if i get 500 miles out of a belt then i'm doing good. with how hard the 115's belts are, they should be lasting longer. look at how long the turbo yamaha belts last pushing 300hp. personally i think the motor moves around too much, even with the new/updated motor mounts. i think ftx's motor plate could make a noticeable difference and it wouldn't take too many 115s to pay for one. and limiting the amount of flex in the motor won't do anything but help the cases/cranks. although the biggest concern with lowering motor movement could increase vibration felt through the bars and running boards. if that was to get bad enough it would be come an issue, ut it would be worth finding out if it saves a few belts over the season.

pv

 

[retiredpop]

I would switch to 18:42 gearing for the heavy wet snow you ride in. Chain length would stay the same.

 

[Rick!]

I would switch to 18:42 gearing for the heavy wet snow you ride in. Chain length would stay the same.

Every time I have geared down from stock I have improved belt life on the hill. My buds in WA gear down with good results, especially on 163's. I used 21/45 on my '11 155 last year. Black was better than black purple in the drive - less heat. YMMV.

 

[Lorduss]

with 18/42
or even 19/42, what does the top speed end up being on eather?
my old edge came with a gearing to MPH chart, i have not seen one with the Pro yet

 

[mt.sledder]

yeah, kind of weird on the pro, but just a fyi, I did install the slp torque arm right off the bat, and stiffer motor mounts...figure my mod sled has motor pretty much bolted in solid and makes 204 n/a legit hp with 3" track, never has it blown a belt...

I really wonder if the soft moveable mounts are a big part of the problem on the pro.????
Oh, if anybodys wondering I took the stock rubber mounts and filled the "gaps" with liquid rubber to firm them up.

If guys are seeing the turbo airbox bolts hit the bulkhead thats 3/8 or more inch away, thats motors moving a HUGE amount in a sled with no torque arm, and this would put massive side load on the belt.

What liquid rubber did you use on your motor mounts?

 

[diamonddave]

Murph,

I'm not sure if it was already rec'd......You may want to consider (I strongly recommend it) sending your primaries to Carls Cycle and having the clutch face mod done at the end of the season. They will recut the faces to be perfect as many (P-85's) are found to not be cut linear over the past few years. This has been a great service for actually reducing clutch temps by lowering belt slip by having a clutch face angle that is actually the same as the belt.

The Carls Helix is also a very huge improvement....lowers temps, makes for better on-off-on throttle performance especially in boondocking and tight tree riding and makes for more consistent full throttle RPM's.

 

[Murph]

DD- my 2011 I sent to Carl's for their mods at end of last season. My 0 mile 2012 clutch I sent to Dan at Indy Specialties. I'll send my clutches back to Dan at the end of the season. The Carl's work was fine, but Dan was faster and did the work himself where Carl's had one place do the machining and another do the balance.

The violent "bounce" I was experiencing was due to user error and a mistimed spring holder and moveable sheave in secondary--nobody's fault but mine. Not helping was a worn out (no cords or visible damage) belt.

As per a suggestion from T R S on Snowest, I am currently using a different weight setup in primary, and different helix and geared down. Both seem to be much superior- without the benefit of really deep snow testing.

Still seeing some belt dust, even though I have checked my alignment with the Polaris LWT special tool. Thinking my rubbers are sacked out in the '12 with 1300 miles and will be ordering some new ones. Thinking of building a push arm on mag side this summer to help keep motor aligned. I think the motor is twisting under load and my riding style is exacerbating the problem. Might also make some rubber insert alternatives-- possibly even delrin.