Grinding mystery ???!!

[Paystar]

Really struggling here,

Been working on a 2018 cross county / thundercat 9000. Parts replaced / added

Jackshaft bearings both ends
Stub shaft bearing
Stub shaft seal
Driveshaft seal
Driveshaft BOP worn shaft fix. (Bearing / collar)
Speedwerx 4th wheel kit
New idler wheel bearings
Prevost top gear bushing and washer.
New track and studs

Everything went into place as it should and not forced. I was able to run the sled on the stand forward and backwards multiple times. No issues. Loaded the sled up and went to the trail head. Unloaded off the trailer and it made the noise in attached video.
Loaded it back up and back on the lift. Took apart the chain case thinking it was gears, everything is as it should be.
Checked the break side and bearing/collar, nothing seems to be abnormal there.
Took secondary off and let the jackshaft free float and pulled the track manually, it would catch and clunk every now and then and would come out of it. Put everything back together, and all was good.
Drove it out in the yard a mile, forward and back. Loaded it on the trailer and when the sled was unloaded it made the noise in the video again. The video makes it seem the kogs are hitting the rail. The attached picture shows the distance between the two.

Trying to pinpoint where the sound comes from is impossible, listen closely to the chaincase and you think it’s the break side and vise versa. It echos in the tunnel.

Hoping to tap into some brainpower here and get my father back on the trail asap!

Thank you in advance!

 

[Goose1200]

I have had a similar noise once on mine once after assembly and it was dry cogs with a dry track. I sprayed wd40 on the drive cods and on the track and ran the sled on the lift and my noise went away. Worth a shot!

 

[74Nitro]

Can't say for sure, but putting new track on worn drivers sometimes causes noise.

 

[Paystar]

I also have the track hanging at 2inches at 20 pounds.

 

[74Nitro]

The drivers were never off the driveshaft?

 

[Turboflash]

I also have the track hanging at 2inches at 20 pounds.

What I hear is track way too loose. Not sure where you might have gotten info on track tension but track should not "hang" off slide rails. Tighter is faster but even on standard duty trail sleds, your track should not hang down off slide rails.
PEFI has their video but some/many think that's too loose. Link: (https://precisionefi.com/en-us/blogs/tech-guide-998/998-track-adjustment-video).
Turbo Dynamics has their own advice. Link: (https://turbodynamics.mybigcommerce.com/td-performance-guide-for-998-turbo-snowmobiles/).

 

[0degC]

Really struggling here,

Been working on a 2018 cross county / thundercat 9000. Parts replaced / added

Jackshaft bearings both ends
Stub shaft bearing
Stub shaft seal
Driveshaft seal
Driveshaft BOP worn shaft fix. (Bearing / collar)
Speedwerx 4th wheel kit
New idler wheel bearings
Prevost top gear bushing and washer.
New track and studs

Everything went into place as it should and not forced. I was able to run the sled on the stand forward and backwards multiple times. No issues. Loaded the sled up and went to the trail head. Unloaded off the trailer and it made the noise in attached video.
Loaded it back up and back on the lift. Took apart the chain case thinking it was gears, everything is as it should be.
Checked the break side and bearing/collar, nothing seems to be abnormal there.
Took secondary off and let the jackshaft free float and pulled the track manually, it would catch and clunk every now and then and would come out of it. Put everything back together, and all was good.
Drove it out in the yard a mile, forward and back. Loaded it on the trailer and when the sled was unloaded it made the noise in the video again. The video makes it seem the kogs are hitting the rail. The attached picture shows the distance between the two.

Trying to pinpoint where the sound comes from is impossible, listen closely to the chaincase and you think it’s the break side and vise versa. It echos in the tunnel.

Hoping to tap into some brainpower here and get my father back on the trail asap!

Thank you in advance!

You said you put new track on. Same as you took off… same pitch? Track pitch matches drivers?

 

[Turboflash]

I have seen and read the advise on tight track tension but in my application I find if I follow the tight track advise my sled does not roll as easily and can be noisy from track clips and sliders but I also don't let it hang too much.

When I watched/listened to video, I see the exit side of the track leaving/being thrust off driver too much which to me means not enough track tension.

 

[Motorhead]

When my 2017 was new, my dealer was showing me a bit of how to on my sled! You know, how to take side panels off, track alignment tips, and he put it on a jack stand so he could start it and spin the track. Told me to listen to that clicking sound of the drivers and track windows, and said that’s normal on these and it will take some time for it to quiet down, so don’t bring it back for that noise!!

Meanwhile my buddy put a skidoo 2.86 on his sled 2-3 years ago and that was loud and stayed loud. He ditched the track after 3-4 long rides because of it!

 

[Paystar]

While turning the track manually.

 

[Turboflash]

I have seen and read the advise on tight track tension but in my application I find if I follow the tight track advise my sled does not roll as easily and can be noisy from track clips and sliders but I also don't let it hang too much.

I only have a Dragy not timing lights so I don't have as scientific documentation as TD does (supposedly) but I think more than a few race guys have documented tighter is faster (if someone care about that). For a standard trail rider, I'm sure it doesn't matter so much but again when I hear that video I went right to track is too loose. And then he says track hangs off slide rails 2"! That's way too much.

 

[Turboflash]

While turning the track manually.

To me, this video sounds like noise is in chain case, not track/track drive. Sounds like tensioner is clanking back and forth. Is tensioner spring broke? Is it correctly installed? Is chain tension set correctly?

 

[Paystar]

You said you put new track on. Same as you took off… same pitch? Track pitch matches drivers?

It had a 137 backcountry 1.75 2.86 pitch. Put a 1.25 ripsaw 2 2.86

 

[Paystar]

When I watched/listened to video, I see the exit side of the track leaving/being thrust off driver too much which to me means not enough track tension.

We had it with the track real tight and it still did it

 

[Turboflash]

We had it with the track real tight and it still did it

Where do you have the limiter straps set?