Clunk sound on take off

[kootsrider]

My 21 Khaos 163 with 300km is "clunking" on takeoff from a stand still. My track tension is correct, track alignment is correct, and my belt deflection is set so the main belt just below the nubs is about 3mm above the secondary, tight but does not squeal at idle. The sled runs great but I cringe a little feeling this on takeoff, happens even when I'm super light on the throttle. I thought maybe it's the sound of the driver hitting the window and it may be more pronounced in Polaris than the Doos I'm used to? Probably just a case of too much mechanical empathy, but if this clunk sound (that I can feel right through the bars) raises a red flag for anyone let me know.

 

[tuneman]

Chain case or belt drive?

 

[live2beel]

Have you looked at your driveshaft real close?

 

[hamlin]

I would guess it’s just the secondary clutch. I’ve noticed it on my sled and everything seems fine

 

[ullose272]

Probaly secondary clutch rollers hittinh the helix

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[kootsrider]

Chain case or belt drive?

Belt drive, which appears normal and fits very tight


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[kootsrider]

Thanks guys, I bet it is the secondary, nuts never heard or felt anything like that from the Doos.


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[Sheetmetalfab]

Thanks guys, I bet it is the secondary, nuts never heard or felt anything like that from the Doos.


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It’s just how team designed the clutch.

Reverse and forward ramps have 1/4” or so wider gap between them than the roller diameter.

 

[simnil]

Thanks guys, I bet it is the secondary, nuts never heard or felt anything like that from the Doos.


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??? Doos clunk like a _______ every time you come back on the throttle from either braking or engine braking. Same "bang" as you get when going forwards again after reversing. Probably one of the reasons the QRS rollers fail so often.

Never had a Team secondary fail, but if the bang bothers you the Team Tied is completely silent.

 

[kootsrider]

It’s just how team designed the clutch.

Reverse and forward ramps have 1/4” or so wider gap between them than the roller diameter.

1/4” of play at the clutch sounds like exactly what I’m hearing. It doesn’t bug me at all as long as I know it’s not something I need to chase down and fix!


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[Sheetmetalfab]

??? Doos clunk like a _______ every time you come back on the throttle from either braking or engine braking. Same "bang" as you get when going forwards again after reversing. Probably one of the reasons the QRS rollers fail so often.

Never had a Team secondary fail, but if the bang bothers you the Team Tied is completely silent.

Funny thing.
I had a team tied clutch and the rollers that keep it sliding without clunking back and forth needed replaced after 1000 miles. (They were fractured and about to fall apart ?)

 

[goforbroke]

I had a sled that did the same thing. I was able to adjust belt tension to make it mostly go away, but then belt squeeled.

 

[Teth-Air]

Kootsrider, it is the secondary rollers hitting and I went through this with my first 2010 Polaris 700. I took it Mainjet to look at as I could not find any problem. They found nothing too. I found that it seemed much worse with a thinned out primary belt, likely it was trapping the secondary or something. Anyway to this day I do hear it more often if my belt deflection is too loose. If you stop by locking the track or stop slowly so the clutches shift properly will show different results. Give it a try. Also reverse to forward.

For those reversing in deep snow this cluck can cause the track to spin some. Try holding the brake while first throttling in reverse to take out the play. Then proceed as normal to avoid the digging in. I have been watching the difference s between the Doo's and Polaris in our group to see why the Doo's are backing up easier. The back of their ski helps too as its longer and tipped up more.

 

[kylant]

I thought maybe it's the sound of the driver hitting the window...

mine does this. on and off the throttle. track shift. this track (165) does it more than any other sled I have run