600 carb maxing out at 7800

[600 rmk 144]

When new this sled would pull to 8400 all the time. Now the most I get is 7850 with occasional peaks of 8000. I installed a new 115 belt, set the deflection, tried all different deflection settings. I've never changed the weights or springs, in fact i've never taken a clutch apart, period. Could cleaning the clutches make that big a difference? And if so, what's the best way to do it? I'm under 2000', above 15 degrees for the most part, running factory recommended jetting & clutching on a bone stock motor.

 

[retiredpop]

When new this sled would pull to 8400 all the time. Now the most I get is 7850 with occasional peaks of 8000. I installed a new 115 belt, set the deflection, tried all different deflection settings. I've never changed the weights or springs, in fact i've never taken a clutch apart, period. Could cleaning the clutches make that big a difference? And if so, what's the best way to do it? I'm under 2000', above 15 degrees for the most part, running factory recommended jetting & clutching on a bone stock motor.

Yes, you could have a weak primary spring which will drag down the rpm. At the very least change it out. You can do it without removing the clutch. Take the cover bolts off to get access to the spring. Yearly clutch maintenance is advisable. Remove both clutches and clean them. You need to get some clutch tools if you want to do it yourself. You can buy them from Polaris or aftermarket companies.

 

[BadgerND]

IMO I think you should take your clutches off every year and clean them. I pull the weights out as well to make sure that the pins are still in good shape. I also weigh my weights and balance them. I've seen weights that are a gram more or less than they're supposed to be.

 

[TaylorSledWorks]

Check the rollers for flat spots and see if your wieght bushings are worn out(leaning crooked ) Also a gummed or stuck exhaust valve will rob top rpm as well.

 

[600 rmk 144]

A friend suggested marking the inside of the clutches with a fat marker, running wide open, and checking to see how much of the marks is worn off. I did it and all but about an inch at the top of the primary was worn off, does this mean a weak primary spring?

 

[havari]

I had the same problem last season and finally figured it out this year when i changed the secondary spring. Had tried everything before that.

 

[600 rmk 144]

So I pulled apart the secondary to check out the spring & found little chunks of aluminum... Turns out somebody parked the sled in reverse and used the L-wrench to spread the sheaves & take the belt off. So there's a nice little hole in one sheave and the thrust washer. And... the dealer can only sell the whole clutch for $438. I know a really good welder who can fix it up but I still don't know if that caused the low rpms. Guess I might as well slap a new spring in while I have it apart.