So last year my buddy picked up a sled its a 98 ski doo formula z 670 its a beautiful sled he was scared of it for sure never wanted to rde it bc its a beast so I ended up riding it last winter and the guy he got it from said it is bored over to a 700 I dont believe it but whatever lol he also said its got a racing clutch setup in it. But when I hit the gas and it starts to go there is like a thump and then when im going like 5 or 10 miles an hour its like a bull lunging forward but when I hit like 20 or 30 it rides fine u can cruze at about 30 mph but anything under like 20 25 it lunges forward im just trying to figure out if its normal or not lol never really had a sled with any aftermarket parts but im deff not kidding the sled is a monster
I dont kno if its ok or not lol
- Thread starter dirtnap315
- Start date
Check belt deflection (belt even with or slightly above top of secondary sheave typically) and that the belt is not excessively worn, correct belt etc...
Oh so your saying it could be out of adjustment so by the time it does catch it is high rpms so it thumps? But why wont it cruze any lower then 20 mph
If the belt deflection is too loose it is like starting out in a higher gear. This is the most common cause of what you describe, hopefully thats all it is.
Finally made some progress
Ok today i worked on the sled all day getting it ready for winter i was trying to figure out my belt deflection and stuff but then i noticed when im reving the sled and i get right around high enough for the clutch to engage it starts moving towards the belt and it seems to get stuck in this one spot so i rev it more and it makes like a thump noise and it hits the belt and starts moving. Also when i let off the gas and the clutch is disengaging it hits that same spot gets stuck for a sec and then you hear a thump and its all the way disengaged could that be bc of the person i got it from did work on the clutch bc i guess it has a clutch kit in it. Im thinking no bc why would it get stuck like that when its backing off when i let off the throttle. Anyone have an answer for me im thinking overhaul on clutch or buy a used one and save a lil money
Ok today i worked on the sled all day getting it ready for winter i was trying to figure out my belt deflection and stuff but then i noticed when im reving the sled and i get right around high enough for the clutch to engage it starts moving towards the belt and it seems to get stuck in this one spot so i rev it more and it makes like a thump noise and it hits the belt and starts moving. Also when i let off the gas and the clutch is disengaging it hits that same spot gets stuck for a sec and then you hear a thump and its all the way disengaged could that be bc of the person i got it from did work on the clutch bc i guess it has a clutch kit in it. Im thinking no bc why would it get stuck like that when its backing off when i let off the throttle. Anyone have an answer for me im thinking overhaul on clutch or buy a used one and save a lil money
you could check your rollers and ramps in your clutch or maybe broken spring just a couple more things to look for
yeah im going to check it all out i just gotta get the tools to pull the clutch lol and i would like to have the money to get the parts to 
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