Snowmobile Racing

heath's proxcr800    ,   thought i figured it out , but its still doing it .

doesnt do it running 660 , but does 1320  ,   when he chops the throttle in the shut down , the thing dont need brakes ,  something is slowing the vehicle without him touching the brake so bad it reverse ratchets the track violent ,  he has to give it throttle to stop it ,  i've been strait thru the clutches , they are fine ,  strait thru the chain case and drive cogs/axle , it did it with the 1000 motor and now with the 800 ,  totaly different skid and it still does it , there is no unusual wear marks inside or out side of the track,   seems fine on excelleration  , only does it at speed when throttle chopped ,  if he had any fillings in his mouth , he'd of probasbly lost them by now.....i'm perplexed

Track is tight I assume??

track is tight ,  key is ,  it stops without brakes  , he has to give it throttle to get to the end and its not a long shut down ,     mine will rev ratchet to if i grab to much brake ,   thats what his is acting like without even touching the brake.

Ron

Not sure if this helps, but on my ski doos w/ rer clutches, they backshift so wicked, after the stripe, that it feels like I waded the bakes and down shifted to first gear. At cicero I had to drive it through shut down. The ratcheting deal right off the bat sounded like a track too lose, but if its tight... or does it back shift like mine and the track balloons. Does that make sense? The other thing I just thought of, was, what about suspension movment. A cat skid will keep tention under power and sometimes ratchet on let off.

What about these guys last year complaining about track pitches being off a wisker. Under power it stretches enough not to ratchet but on let off the track cools a little. Dunno just throwing some thoughts out there.

Vince

the back shifting is all that makes sence ,   never had one do it ....though ,  

Ron, is it the opposite. Maybe not backshifting quick enough on letoff, or the belt flopping around because one backshifted and the other didn't?  Cogs riding on the bottom of one of the clutches?

thats what i thought at 1st ,  did everything to the clutches i could think of , nothing different from what i always ran ,   but this stripped pro-x chassis is lighter than anything i've ever ran , maybe thats effecting the back shift,  dont know , gonna tighten the track up more , at least gotta stop the rev. ratcheting , or something is gonna break...

Ron my xcr has done it before too. Thought I was running up on the drive cogs. Almost violent when ya lift. I tightened the track. 

 HMMMM, seems i mentioned something in another thread about this very thing........ gotta love centifugal force....... tell him he'll need to learn how to use the throttle to stop as mentioned before. 2 strokes at high speed WILL engine brake, you cannot expect a motor reving at full throttle with agressive up shifting clutch setups to drop the belt as soon as you chop the gas. sorry.

Ron, My XCR did the same thing when I was using aluminum drive sprockets. Had to spray silicone to help it. Ended up going back to plastic. Aluminum drivers bite into the track eventhough the pitch is the same. Hope you get it straitened out, see you next weekend.

well , its almost completly stopped ratcheting , gonna have to move the skid back to get more tension , worked good enough for him to get the win yesterday.....lol   

Maybe a worn out shock too that doesn't rebound fast enough to tighten up the suspension after the long run sucked down.