Driveline vibration under load

[ippielb]

Sled is a 2012 proclimb 800, has a supercharger on it. Cruising it doesn’t vibrate but when I crack it open and load it up, the sled vibrates in my feet. It did it last time I rode it but I thought it was the track tension...

Secondary helix bolts are there and tight
Jackshaft bearing PTO side tight and clean.
Chaincase was just opened and inspected and fresh oil, nothing was wrong, has the auto tensioner still.
Trackshaft is tight no play
Track tension and alignment is good.
Have antistab kit installed.
Track is only a 2.5 and not hitting anything.

I’m reading about a bent jackshaft or track shaft. Where do they bend? In the middle where one can check it or right at the bearing flange that would make it wobble when driving?

With the added torque from the supercharger would it be the chain skipping over the teeth of the gears because of the wonderful auto tensioner?

 

[Lund]

Sled is a 2012 proclimb 800, has a supercharger on it. Cruising it doesn’t vibrate but when I crack it open and load it up, the sled vibrates in my feet. It did it last time I rode it but I thought it was the track tension...

Secondary helix bolts are there and tight
Jackshaft bearing PTO side tight and clean.
Chaincase was just opened and inspected and fresh oil, nothing was wrong, has the auto tensioner still.
Trackshaft is tight no play
Track tension and alignment is good.
Have antistab kit installed.
Track is only a 2.5 and not hitting anything.

I’m reading about a bent jackshaft or track shaft. Where do they bend? In the middle where one can check it or right at the bearing flange that would make it wobble when driving?

With the added torque from the supercharger would it be the chain skipping over the teeth of the gears because of the wonderful auto tensioner?

Have you looked at your driver's or drive shaft end play. There should be non.
I have seen a drive axle on a Doo once break because it was tweaked. The guy who owned it complained about it having a new vibration at his feet and couldn't find it. Rode it for a few 100kms and one day out there the axle snapped from metal fatigue.
I broke an axle before but that was very noticeable, sled was undriveable.

 

[ippielb]

Have you looked at your driver's or drive shaft end play. There should be non.
I have seen a drive axle on a Doo once break because it was tweaked. The guy who owned it complained about it having a new vibration at his feet and couldn't find it. Rode it for a few 100kms and one day out there the axle snapped from metal fatigue.
I broke an axle before but that was very noticeable, sled was undriveable.

Had the chaincase open last week never noticed anything on the chaincase side, never tore into the brake side because I took a pry bar and reefed on the shaft in a few different ways and never got any movement.

Driver’s didn’t look anything out of ordinary, windows aligned with the teeth.

If I drive the sled nicely without romping on it, it doesn’t vibrate. But when the skis don’t touch that’s when it does.

 

[jhurkot]

Have you tried watching the driveshaft while you spin it on the track stand? Could just set up your phone to record a video of the shaft spinning and see what track speed produces the vibration.

 

[FernieHawk]

Had the same thing on my 2008 M1000...couldn’t figure it out and we looked at almost everything. Then the Helix blew up. Problem solved.

 

[ippielb]

Have you tried watching the driveshaft while you spin it on the track stand? Could just set up your phone to record a video of the shaft spinning and see what track speed produces the vibration.

Never got that far, if my shop was heated I’d be fooling around all evening long every day. But -30 gets old fast trying to wrench on stuff.

Had the same thing on my 2008 M1000...couldn’t figure it out and we looked at almost everything. Then the Helix blew up. Problem solved.

I’ll have to take my secondary apart and check my helix. I have a spare I could try.

 

[FernieHawk]

The vibration was only under load...we put it on the track stand and couldn’t replicate the problem as it was not under load. Primary and secondary seemed to be operating properly. I believe there must have been a crack in the helix that we didn’t see and then it finally let go. All the screws were still intact in the sheaves. Vibration was gone with a new helix installed.

 

[Allseasons]

Yes check helix x2.

Do you have Anti stab on skid? If not, under load track windows catching skid tips? Check track tension

 

[ippielb]

Yes check helix x2.

Do you have Anti stab on skid? If not, under load track windows catching skid tips? Check track tension

Antistab is installed, track tension is set to 3-4 fingers at the middle with ten pounds weight.

I wish it would warm up so I could go check this stuff. Shift work sucks for getting stuff done when you’re working. Same with -35 windchills for a high.

 

[Allseasons]

IMO too loose. I run 2 fingers at 20lbs. I bet the guides are hitting tips. That 3” likes to be tight

Flat spot on belt?

 

[ippielb]

Bent driveshaft.... can’t tell by looking at it, but with a straight edge down the tube can see it’s bent quite a bit. Ran it on the stand and could see a little wiggle. now to find me a replacement.

 

[ippielb]

After taking a few dozen pictures I finally got a picture at the right angle to see the bend.

 

[killerrf]

Bent a driveshaft on a diamond drive which after hit the rock had a vibration at feet. Setting it up on vice to rotate it was like only 70-80 thou out of round. Found a good used shaft then vibs gone. My m8000 also has a vib under heavy load which it isn’t bad as the diamond drive shaft is but still can tell some vibs there. I did notice the shaft has some side to side end play which I’m not sure if that’s normal.

 

[ippielb]

Bent a driveshaft on a diamond drive which after hit the rock had a vibration at feet. Setting it up on vice to rotate it was like only 70-80 thou out of round. Found a good used shaft then vibs gone. My m8000 also has a vib under heavy load which it isn’t bad as the diamond drive shaft is but still can tell some vibs there. I did notice the shaft has some side to side end play which I’m not sure if that’s normal.

Check the snap ring on the brake rotor. And the 3 bolts that hold the bearing on the bulkhead at the brake as well.

 

[Lund]

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After taking a few dozen pictures I finally got a picture at the right angle to see the bend.

It was a bent axle, kinda figured that, it’s not that uncommon. Now with Cats D&R cases we are going to see a lot more of these bent axles and damage drivers. Including cases.
That was the the biggest problem we had with this mod back in the day.