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Discussion Starter · #1 ·
Took my F III out for a run today. Sled works absolutely great, hard pack trail or soft snow, I hold 8200 rpm. However, my primary seems to make a howling, squealing noise around 6500-7000 rpm. If I drive slow, I don't hear this noise, or when I have it wide open. Primary and secondary have been off and cleaned, belt is in good shape. Bottom end has been redone after taking out pto side bearing, and is getting plenty of oil. Any ideas what is causing this squealing
 

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Ah, that dreaded F chassis clutch howl. Been thru it with mine from the 600, 700, 780 AND the 925, lots of different set ups. The noise is belt slip. The factory belts were sled/set up specific compound (hardness) in the late 90's. The dealers no longer carry the "specific" belts for these sleds, just a generic fit. It takes some work/time but you'll have to run your clickers on 2-3 for trail riding (more side pressure on the belt) and crack them up to 4-5 for speed. Most of the time I just live with it and rough the sheaves and belt with emory cloth before a speed run or race.
 

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Discussion Starter · #3 ·
I have had this sled since new. I have always lived with a minor amount of squealing, but nothing like what I have now. When I clean my clutches, I use emory cloth. I have a bombardier belt on my sled when this howling occured. I have an ultimax as a spare. Any particular belt better in my circumstance?
 

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saskrev said:
I have had this sled since new. I have always lived with a minor amount of squealing, but nothing like what I have now. When I clean my clutches, I use emory cloth. I have a bombardier belt on my sled when this howling occured. I have an ultimax as a spare. Any particular belt better in my circumstance?
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Does the noise go away for about one ride if you put a NEW belt on?
 

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Discussion Starter · #5 ·
I'll have to find out. The bombardier belt has maybe 450 miles on it. Ultimax belt is a spare and I put it on when towing my kids on their sno racers.
 

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Towing the kids around? Mine only gets loud in the twisty trails. If you spend alot of time cruisin" or "puttin around " on a triple the clutches and belt will dirty and suffer. The F-lll was set up to run hard! We've done a few in the shop here and doo have the best luck with Bombi belts. I've run the Ultimax on some of our earlier twins with no problem though. Check out both your primary and secondary clutch springs, they will loose strength (pressure) with use. One Bud of mine with a 96 600 went thru the dealer to fix this and they turned his TRA clickers down to 2 and told him to live with it.
I bought mine as a demo and like I said earlier, I didn't run into this until i did the clutches...maybe the replacement parts suck???
 

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Which Doo belt are you using? Try scuffing up the sides of the belt, could be glazed. Replace the clutch springs if you haven't in the last couple years.

I never had an issue with any belt slipping in any of the F chassis sleds I work on every year. 5 FIII 6's, 3 Mach 1's, and 7 Mach Z's. All run the -127 doo belt, most are stock clutched, some have clutch kits.
 
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