When you observe fluctuating rpms; 1) high rpms on road and low rpms in the snow, or
2) Correct rpms for moments at full throttle but watch the rpms diminish, then ( and i know it is not pleasant to measure ) you must check all bushings to see if they are near or at the wear limit. If the bushings are heading towards the wear limit then the clutch fitness itself can be causing the rpm fluctuation when all the engine management is fine and working well.
Helix bushing - Product specs
No need to buy a shiny flavour of the week aftermarket secondary - the addition of these phenolic resin make for...
- Clutch roller service life dramatically increased.
- Longer belt life.
- Rollers are made from hi-tech extremely durable material
- Highly resistant to heat and distortion.
- No more flat spots or skidding.
- Clutching and tuning made easier due to consistent action.
- Quicker backshift gives better throttle response.
I recommend these secondary rollers especially in any 2008~2010 trail or mountain model XP sled.
Pivot stud fastener device
2008, 09, 10, 11 have the D-Clip which holds in the pivot stud.
2012 has a threaded screw to hold in the pivot stud.
2013~16 has a steel compression roll pin pressed into the casting to hold the pivot stud.
Dont forget to double check on the swivel washers that go on either end of the secondary spring. One has the secondary out and a swivel will fall on the floor or just disappear. Confirm there are two washers on either end of the spring, have no metal on metal.
One of the best modifications i've ever used for alignment issues that cause torn out chords on belts.
Doodoctor at Youtube - click
REV XP chassis types please note the following specifications.
"Z" Distance 21.0mm .827 in.
"X" Offset 37.1 +- 0.5mm 1.461 +- .020 in
"X-Y" Difference 1.62mm 0.064 in.
Please note: Although these are the target specifications, pulley alignment is not adjustable. These dimensions are for reference only.
Doodoctor's Floating Secondary clutch is excellent to fix what ails your alignment
Alignment changes after Break-in
The primary clutch fixed sheave crankshaft taper may not be impressed far enough into the clutch and can give a further-away relationship to the engine, which will change the X dimension and alignment. ( my personal 08 xp had this problem and solved with doodoctor floating secondary . My alignment was 1.2mm out even after a full shim kit behind the secondary shaft jackshaft bearing ) If that measurement is in question then borrow or get another tra-7 primary clutch and put it on the engine to verify this measurement to eliminate the possibility of such an out of place event as I have experienced.
The engine back stop can move out over a 1/4 inch. The clutch alignment can be good at rest however under full load the torque would twist the engine out of parallel.
Andrew) I am having belt bowing issues on my 2015 800 bcx it is stock please help its getting expensive what can I do
Joey) What is your percentage of on/off trail? Do you also get to run the sled at highest track speeds over 95mph? Do you run in deep snow all the time?
Andrew) 50 % off trail 50% on trail. I do like to run at high speed at times
Not always in deep snow to be honest 2 belts disintegrated running trails in the UP. Clutches get smoking hot. I do run some deep snow as we do to idaho a few times a year . Top gear is 23.
Joey) Going past 98mph will blow a belt with a 23 top gear
You could benefit from doing a different alignment – making the X of the secondary clutch shaft stick out more
You have 36.4 in the X on alignment and can probably use 39.4 on the X like a summit
That will be a good start – do a new alignment spec. Stay below 98mph track speed.