Lets talk hot fixed sheave on inside primary

[KnappAttack]

So been riding lots the last few weeks. I never really notice the hot fixed primary in cold temps, but when the ambient temps get up there into the high 20's and low 30's as it gets warmer now, I'm seeing black streaking on the inside of the primary and secondary. I also notice the RPM goes in the toilet as the belt gets hot which is to be expected.

I thought maybe I needed to try floating the secondary, so I set it up to float yesterday. Conclusion, floating didn't help a thing. Inside sheave still hot! Outside movable is actually extremely cool along with the secondary being cool. It's not an alignment thing and its not a clutching thing. We had three Sidewinders yesterday all with different clutching components, belts and different tunes, and everyone of them had the exact same thing going on. About 30F ambient and all 3 had hot inner primary sheaves and cool movable secondaries. All 3 sleds were getting flogged hard and we were having fun with them.

I'm going to be installing some type of fan and ducting going to the backside of the primary and the inside of the belt to try and cool the inner sheave and belt down. Just the fact the clutch is bolted and attached to a engine with 170* water temp and even hotter that 200* oil temps there is no way to get away from the fact the clutch is attached to a heater. It needs cold air blown on the backside of the primary and thats all there is to it. Can't run in 0*F air all the time, so going to need to do something to get heat down on it, and yes, I have vents galore up front along with the Fleecer scoop mod and venting out the back of the panel.

 

[ROCKERDAN]

Mike I noticed my inside fixed sheave of primary very hot many weeks ago. While movable is literally COLD much of the day. I floated and moved offset, and it remained hot as yours did.

I attribute this to my Stub shaft pulling heat off crank end(heat sink). But I know my stub is pushed inward some, and so would not think they all are this warm.

Dan

 

[KnappAttack]

Mike I noticed my inside fixed sheave of primary very hot many weeks ago. While movable is literally COLD much of the day. I floated and moved offset, and it remained hot as yours did.

I attribute this to my Stub shaft pulling heat off crank end(heat sink). But I know my stub is pushed inward some, and so would not think they all are this warm.

Dan

It appears Dan they are ALL hot.

 

[74Nitro]

I went out and did some full throttle pulls up and down a half mile field(can u say fun!). I took an infared temp reader with me, then quickly checked sheave temps after stopping. I wasn't able to read the face of the movable since I couldn't read the tool when held that way. I did measure the top edge of both sheaves and there was 15 degrees celcius difference. Also, when the upper portion of the fixed sheave was reading 70, down at the bottom was about 80

 

[STAIN]

there is a company that makes a shield to keep the motor heat from these clutches. I'll have to find it....

 

[74Nitro]

there is a company that makes a shield to keep the motor heat from these clutches. I'll have to find it....

I think the heat is travelling through the PTO shaft into the clutch, more so than the heat thrown off the engine.

 

[kinger]

Wouldn't that be true of every snowmobile made? They are all attached to hot engines.

 

[KnappAttack]

Wouldn't that be true of every snowmobile made? They are all attached to hot engines.

No where near that hot on a two-stroke. Four-strokes yes, but this Winder seems to have little to no airflow getting to the inner primary sheave to help cool it down.

 

[1nc 2000]

Same here. Clutches cool except the fixed primary sheave. I just cleaned off a black rubber stripe like a John Force burn out off my inner sheaves.

 

[Big_Phil]

Same here, the inside of the belt gets hotter than the outside of the belt.

 

[Crossfire12]

Frank Belinger on HCS was selling a shied that went behind clutch ,covering the whole area ,sealing the clutch compartment from the motor, this was for the 1100, He had a web site maybe you can look at how he did it and make one yourself, it was sheet metal. No motor heat would get in clutch compartment, and clutch side had vents and some used a fan. The web site is Belinger racing products.com there is a picture, I can’t get the picture over here,

 

[Crossfire12]

Guard

 

[STAIN]

This is from HRP

 

[buddah]

I vaguely recall some Polaris guy selling some low-power fan apparatus that mounted to the belt guard that he claimed lowered belt temp by 40 or so degrees....this was almost 20 yrs ago but I don't think it ever went anywhere...

I would think some "engineering marvel" could figure out how to do some sort of ram air thing like the drag racers did with hood scoops back in the 60's...biggest issue would be filtering to keep snow dust out....way beyond my capabilities....

 

[Crossfire12]

Fan on 1100s, 4 in derailed fan low side panel blowing onto secondary, ran cool, had it on mine, But I’m not having trouble with hot belts on my 998,