JackShaft & Bearing Problems

[geo]

IMO it is pulley alignment or changing alignment (for reasons described by LH).

PV, when the top pulley etc. is off the shaft do you need to push the QD plate in to contact the top bearing to the step in the jackshaft? This was my scenario and shimming and torque eliminated much of the top-pulley-heatitis I had.

This year (right now actually) I'm "completing the box" between the drive shaft and jackshaft to be more secure and rigid. I hope to strengthen the tunnel in this area at the same time so the suspention does not add to the possible twist in this area with plates on the inside.

 

[rockinmranch]

Jackshaft Number Four

These pictures should help to remove doubt to what is going on with the belt drive. This out out af a 2013 pro rmk use as a rental sled. It had 2500 miles when this shaft was replaced on the right, new shaft for comparison on the left. I ran the new shaft in it another 1000+ miles. The new shaft now looks like the old shaft. No doubt the shaft is turning inside the bearing, which is also causing extremely high top sprocket temps. Maybe regluing the bracket or bolting it is the answer. I have got to believe Polaris will be coming out with a fix soon. I bet there are many more sleds out there with this problem than are not recognized at this time. The problem surfaces with mileage and the sled will still run with the bearing in the shape as pictured, it just starts to clunk on hard excellerations.

Installing jackshaft number four on my 2013 pro RMK. It was replaced new at the beginning of the season. Made it fourteen days before it looks like my picture in the above post from last year. Dealer says they may not be able to warranty. I was hesitant to do the fix (prescribed in this thread) for myself for fear of messing up my warranty. The answer from Polaris is torque to 45 and all is good. This is absurd. It baffles me that Polaris will not publicly admit a problem, yet expect us in the snowest community to remedy it ourselves. In my opinion the sled is a "Lemon" Nobody at Polaris knows how to properly fix it. I will be trying the fix of regluing and installing the bearing bracket. I hope it works. Doesn't appear to be very much excessive space between the bracket and the bulk head.

 

[rockinmranch]

Jackshaft Number Four

These pictures should help to remove doubt to what is going on with the belt drive. This out out af a 2013 pro rmk use as a rental sled. It had 2500 miles when this shaft was replaced on the right, new shaft for comparison on the left. I ran the new shaft in it another 1000+ miles. The new shaft now looks like the old shaft. No doubt the shaft is turning inside the bearing, which is also causing extremely high top sprocket temps. Maybe regluing the bracket or bolting it is the answer. I have got to believe Polaris will be coming out with a fix soon. I bet there are many more sleds out there with this problem than are not recognized at this time. The problem surfaces with mileage and the sled will still run with the bearing in the shape as pictured, it just starts to clunk on hard excellerations.

Installing jackshaft number four on my 2013 pro RMK. It was replaced new at the beginning of the season. Made it fourteen days before it looks like my picture in the above post from last year. Dealer says they may not be able to warranty. I was hesitant to do the fix (prescribed in this thread) for myself for fear of messing up my warranty. The answer from Polaris is torque to 45 and all is good. This is absurd. It baffles me that Polaris will not publicly admit a problem, yet expect us in the snowest community to remedy it ourselves. In my opinion the sled is a "Lemon" Nobody at Polaris knows how to properly fix it. I will be trying the fix of regluing and installing the bearing bracket. I hope it works. Doesn't appear to be very much excessive space between the bracket and the bulk head.

 

[rockinmranch]

Also does anyone know if fusor 108 b is sufficient for the fix. It is what my napa can get. Need to order in the morning.

 

[LoudHandle]

Also does anyone know if fusor 108 b is sufficient for the fix. It is what my napa can get. Need to order in the morning.

108B is fine also, same stuff just longer work / cure time. Where the 110B is 5-8 minutes before it starts to kick and harden. The 108B gives you about 40 minutes to get everything perfect before kicking and starting to cure.

 

[rockinmranch]

Thanks. When I pull the bracket will I need to heat the old adhesive to release or can I simply pry the bracket off?

 

[LoudHandle]

Thanks. When I pull the bracket will I need to heat the old adhesive to release or can I simply pry the bracket off?

You will need to heat it up, you can put a light pry on it while heating, but prying alone will do nothing but damage things.

 

[geo]

RR. 4th shaft? That's not good. Something is being reinstalled that shouldn't be IMO. If the torque stays (bolt remains tight), even if the bearing goes the shaft should not be damaged (aligned or not).

You must be on a '14 shaft now (longer shouldered bolt for the top pulley) so there are 3 other things to pay close attention to.
The disc brake is a spacer too. Look at the inner end of the hub that tightens against the bearing. Is it deformed (not flat, mushroomed slightly into the shape of the bearing race). That disc is made of soft material (has to be for brake friction).
You can replace the disc (maybe Poo changed the design) or a better repair is the take 30 thou off that side and replace that distance with a shim of the same thickness (the ones you use for behind the secondary work great).
Now you have much more surface area to torque against the inner race. Enough that it should not mushroom again.

Next check if you have any clearance between the end of the shaft and the face of the pulley. Mine was so close to flush (if it is flush the washer will bottom out on the shaft and not apply the bolt torque to the pulley). The '14 shaft may be different but I added 10 thou to the shim between the disc and bearing to get some clearance there.

The other thing to look at closely Is the spring washer for the pulley bolt. Mine was too relaxed (flat) and the OD was too large. The OD was larger than the cast in steel insert on the pulley gear so it was actually torqueing on aluminum not steel during initial set. Not right and as soon as the aluminum gave the torque was lost (you can see the shiny on the pulley face and the outer edges of the washer).
A Doo jackshaft washer is about 100 thou less OD and made of slightly thicker better spring steel (4 loonies though lol). It returns to a conical shape after disassembly.

When you reassemble use high heat green locktite on the pulley bolt and take it to AT LEAST 45 ft lbs and let it cure over night (I also used it between the inner race and jackshaft cause it was there).

Like I said before, if the torque stays, short of a complete failure on the bearing, the inner race should not spin on the shaft.


If you take your time to straighten out the chaincase OR shim the jackshaft ( so C to C bearing to bearing is correct) you will see a lot less pulley heat.
My sled needed 50 thou behind the chaincase on the jackshaft and 30 thou outside the tunnel on the drive shaft to take out the side load on the bearings.
Not much when you consider the big picture but enough to make my bearings grumbly in 1700 miles. New bearings are happy happy lol.

 

[tbeaton]

mine milled itself down a well. I have jut over 1000 miles and I'm the only one that I know of that had this happen. I ride with a bunch of guys on rmk's and I know a handful of them are 13's. somehow my qd belt was fine and who knows how long I ran it like that. I guess I will have to keep an eye on it.

 

[maxitout77]

Tbeatons shaft...

 

[rockinmranch]

RR. 4th shaft? That's not good. Something is being reinstalled that shouldn't be IMO. If the torque stays (bolt remains tight), even if the bearing goes the shaft should not be damaged (aligned or not).

You must be on a '14 shaft now (longer shouldered bolt for the top pulley) so there are 3 other things to pay close attention to.
The disc brake is a spacer too. Look at the inner end of the hub that tightens against the bearing. Is it deformed (not flat, mushroomed slightly into the shape of the bearing race). That disc is made of soft material (has to be for brake friction).
You can replace the disc (maybe Poo changed the design) or a better repair is the take 30 thou off that side and replace that distance with a shim of the same thickness (the ones you use for behind the secondary work great).
Now you have much more surface area to torque against the inner race. Enough that it should not mushroom again.

Next check if you have any clearance between the end of the shaft and the face of the pulley. Mine was so close to flush (if it is flush the washer will bottom out on the shaft and not apply the bolt torque to the pulley). The '14 shaft may be different but I added 10 thou to the shim between the disc and bearing to get some clearance there.

The other thing to look at closely Is the spring washer for the pulley bolt. Mine was too relaxed (flat) and the OD was too large. The OD was larger than the cast in steel insert on the pulley gear so it was actually torqueing on aluminum not steel during initial set. Not right and as soon as the aluminum gave the torque was lost (you can see the shiny on the pulley face and the outer edges of the washer).
A Doo jackshaft washer is about 100 thou less OD and made of slightly thicker better spring steel (4 loonies though lol). It returns to a conical shape after disassembly.

When you reassemble use high heat green locktite on the pulley bolt and take it to AT LEAST 45 ft lbs and let it cure over night (I also used it between the inner race and jackshaft cause it was there).

Like I said before, if the torque stays, short of a complete failure on the bearing, the inner race should not spin on the shaft.


If you take your time to straighten out the chaincase OR shim the jackshaft ( so C to C bearing to bearing is correct) you will see a lot less pulley heat.
My sled needed 50 thou behind the chaincase on the jackshaft and 30 thou outside the tunnel on the drive shaft to take out the side load on the bearings.
Not much when you consider the big picture but enough to make my bearings grumbly in 1700 miles. New bearings are happy happy lol.

Geo I just came home and looked at this sled after reading your post. I think you may have nailed it on this sled, I'm hoping. When I look at the union of the chaincase (QD) to the tunnel I see no space between the plate and the tunnel, or at least any more than would seem normal. The four tabs with the studs that sit towards the back are all flush to the tunnel, a little glue squirting out from one. When I put the old shaft back in, I notice that the top gear sits flush with the shaft, therefore it must be bottoming out on the washer. Also the washers are nearly flat now. The back of the rotor is mushroomed and it is starting to contact the bearing retainer. I am thinking rather than a reglue, a few new parts may be the answer. I will plan on ordering a new rotor and fresh washers, all other parts will be new except the top gear. I hope this is the fix. If not, I'll reglue on shaft #5.

 

[dexter]

Is there no way o check this without disassembly ?

 

['77 Rider]

Hi everyone,
New to the site and new to Polaris.

Contemplating buying a 2014 ProRMK 600 and would like to know if these problems were addressed and properly fixed for the 2014 model year. Any other things to look out for would also be great!
Thanks for your help!

 

[mountainhorse]

ttt

 

[rockinmranch]

Update

Geo I just came home and looked at this sled after reading your post. I think you may have nailed it on this sled, I'm hoping. When I look at the union of the chaincase (QD) to the tunnel I see no space between the plate and the tunnel, or at least any more than would seem normal. The four tabs with the studs that sit towards the back are all flush to the tunnel, a little glue squirting out from one. When I put the old shaft back in, I notice that the top gear sits flush with the shaft, therefore it must be bottoming out on the washer. Also the washers are nearly flat now. The back of the rotor is mushroomed and it is starting to contact the bearing retainer. I am thinking rather than a reglue, a few new parts may be the answer. I will plan on ordering a new rotor and fresh washers, all other parts will be new except the top gear. I hope this is the fix. If not, I'll reglue on shaft #5.

Just updating all that have been following this thread. Four jackshafts later, geos recommend fixed my issues..... In my case it was not the plate being spaced from the tunnel, but the back side of the brake rotor was worn from time spent spinning against the other components. My jackshaft problems typically surfaced again after five or so rentals. This sled has now done 20+ rentals and all is well. Anyone with this problem, makes sure your dealer is replacing all parts, bearings, rotor, washers, bolts, shaft etc. Thanks for the info Geo!!

 

[geo]

Your welcome and keep your bolts tight lol.

 

[CLAYL]

Should the brake disc have side to side movement? The back side is mushroomed and i want to clean it up but not sure of how much of a spacer and should it be up against the inner race of the bearing. Thanks.

 

[LoudHandle]

Should the brake disc have side to side movement? The back side is mushroomed and i want to clean it up but not sure of how much of a spacer and should it be up against the inner race of the bearing. Thanks.

The brake disk should have zero axial movement. The backside is mushroomed because it was too loose from the factory. If it is, it is likely the shaft (radially) is worn too much from it spinning in the inner race of the bearing to save.
The inner race of the bearing, brake disk hub, and QD pulley all need to be torqued together or you will continue to have issues.

 

[CLAYL]

So clean up the disc, put it back together and figure out the amount it moves and make a shim a bit bigger so its against the brake disc and bearing? Just doing a quick fix for the season then fix properly in off season. There is some gap between the plate and tunnel. There is a tki belt drive on mine so not sure if it makes a difference(no wave washer). Do you know if the pulley to jackshaft should have a space like a QD should? Bought it used last season. Wish i would have known about this in the summer(no garage).

 

[LoudHandle]

So clean up the disc, put it back together and figure out the amount it moves and make a shim a bit bigger so its against the brake disc and bearing? Just doing a quick fix for the season then fix properly in off season. There is some gap between the plate and tunnel. There is a tki belt drive on mine so not sure if it makes a difference(no wave washer). Do you know if the pulley to jackshaft should have a space like a QD should? Bought it used last season. Wish i would have known about this in the summer(no garage).

TKI is not an upgrade from the QD in my opinion. But to each their own. None have a wave washer as it would be useless in this application. The bearing, brake hub, pulley stackmust be about a 1:16” longer than the shaft shoulder to end. There should be no gap! QD or not.