What is making the heat on top pulley of the QD?

[geo]

IMO hot-top-pulley-itis is simply chassis blue printing combined with the flexy QD plate.

I had the "itis" in all riding conditions, even though I kept my top pulley tight. My QD belt always rode against the top pulley flange too.
When I had my top pulley off, I noticed i needed to push in a lot (50 thouish) to get the top bearing to contact the flange on the jackshaft. So, when torqued up, the bearing was in a side load condition and the pulleys were misaligned.
I placed the correct shim on the jackshaft so when untorqued the shaft just contacted the upper bearing (did not push out on bearing and did not require push in to contact).
Torqued things up and since then, the "itis" is gone and the QD belt finds it's own center between the upper pulley quide flange and the lower pulley guide flange.
Still have excessive heat after long wide open stuff but it's coming from the muffler because everything (belt, both pulleys, and brake) is hot.

Been trying to break the '13 belt the last few rides in spring conditions so I can use the unreturnable-for-me. spare I have. No luck so far lol. 1700 miles and growing. I'll probably use it next season til it breaks just because.

Why is this more important than on a chaincase like before? I'm sure many Pros were not perfect from the factory (like any other brand) in chassis alignment. Bearings can take quite a bit of sideload before failure.
The big difference is a multi-plate chain has a built in tolerance for mis-alignment. It is flexy when new and flexier when worn. It is also narrower.
The wide rigid belt needs to be closer to perfect alignment especially with the flange to flange guide system that Poo used. If your going to align your pulleys you might as well do it from the jackshaft side to take off the side load on the bearing too.

 

[LoudHandle]

I just completed what I'll call the Geo mod (as he recommened it months ago on here) to a '13 QD PRO. Here are my observations on this sled and what worked for me.

After looking it over the QD looked good, bearing plate tight to chassis everywhere and bearing was pinched as intended. What we did find was the driveshaft bearing on the clutch side that should be a press fit was already worn more than a sixteenth undersized in 472 miles.

After disassembly, removed rear suspension, battery, driven clutch, drive shaft, QD belt and sprocket, brake caliper and disk. I drilled the two top rivets out thru the QD plate (you can see the two raised spots on the QDBearing plate casting to give them clearance for the rivet head). Once you have the pilot in the QD plate and the rivet gone except the flange ring, drill plate again to 5/16". Then from inside the tunnel drill the rivet holes out to 5/16" also. You should just have the rivet flange left. Rather than pry the nicely glued QD plate (in this case) away and re-gluing it, I took a very small flat blade screw driver and deformed the rivet flange on opposite sides and it then falls thru the drilled hole. Since the QD plate on this sled was tight to the tunnel we elected to not add glue and just add the two shortened (11/16" long) Torx drive chassis bolts and bolted the upper plate to the tunnel with chassis nylock nuts. Note the front rib interferes slightly so we removed enough of the rib for the bolt head to sit flat. The shortened bolts and nuts are in the top corner of the tunnel and do not interfere with track clearances. We then reassembled with a new driveshaft with the HappyFace collar glued on and we Loctited the bearing on the other side to hopefully avoid it failing in the next 500 miles.

Note, this sled was owned by a dealership owner and still had obvious flaws. The QD side was as good as I've seen, but the lower clutch bearing shaft to bearing clearances on the shafts need to be checked and appear loose on the shafts I have had my hands on. From that I would recommend Checking them before they wear enough to shear off and getting them warrantied. Loctiting the bearing in place on the new shaft to prolong the life of the shaft.

Hope you find this helpful.

 

[m1kflyingtiger]

Pictures??

I got a laugh out of the beginning of you post, in the cat world the "geo mod" is a rear swing arm upper mount and forward stop relocation that works wonders on how the m-series skid handles.

 

[LoudHandle]

Pictures??

I got a laugh out of the beginning of you post, in the cat world the "geo mod" is a rear swing arm upper mount and forward stop relocation that works wonders on how the m-series skid handles.

I did not take any, I'll document the next Geo mod with pics and post them. It likely would make it a lot clearer for the masses, than reading my verbiage.

 

[m1kflyingtiger]

So my next question, if I do this and something goes wrong with drive system am I on my own as far as warantee?

 

[LoudHandle]

So my next question, if I do this and something goes wrong with drive system am I on my own as far as warantee?

That is for you to figure out. I personally don't do the warantee BS. Never got my money's worth out of any of them I bought in the past. Now I do not play the game. I used the same torq chassis bolts as the rest of the sled, so my guess is most of the minimum wage flunkies that are wrenching onthe sleds at the dealerships would never notice anyway, but that is a decision each individual will need to make.

I would guess Polaris will figure this out soon and add the fasteners in the production sequence, at some point.

 

[Hawkster]

LoudHandle ? Did you happen to notice how well the timing of the belt and pulleys matched up ? Someone posted a picture of the lower pulley and belt and it was really obvious on the drive side the last cog was bending forward from the pulley and the driven side was bending towards the drive side . The belt lugs had no choice but to bend . That would create a lot of heat .

Try a different example , The lug was being forced to move clock wise on contact with the lower pulley and the driven side of the lower pulley the lug is bent counter clockwise .

 

[LoudHandle]

LoudHandle ? Did you happen to notice how well the timing of the belt and pulleys matched up ? Someone posted a picture of the lower pulley and belt and it was really obvious on the drive side the last cog was bending forward from the pulley and the driven side was bending towards the drive side . The belt lugs had no choice but to bend . That would create a lot of heat .

To be honest I did not look at that, I have a couple new take offs in the garage now, I'll go look.

 

[Hawkster]

Found it , sure looks like it's bending the lug ? Follow the teeth .

 

[LoudHandle]

That looks very similar to the ones I have in the garage. That sprocket has obviously been to H e ll and back from the looks of it.

My thoughts; since the sprocket diameter will grow faster than the belt due to the coefficients of thermal expansion for the different materials, the sprocket when warm will grow into the same pitch as the belt. Cold it is a slightly shorter pitch, if it gets too hot it will be a longer pitch than the belt. At proper running temps it should be the same and run fine.

We need to address the previously mentioned bad actors and your QD should run very well for a cheap entry level system.

 

[rockinmranch]

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.

 

[adamg]

You are saying that the shaft turned itself down by like 1/2" just from spinning in the bearing?

 

[LoudHandle]

You are saying that the shaft turned itself down by like 1/2" just from spinning in the bearing?

Exactly! This is why every owner needs to be vigilant and check the fitment on their sled. If your not mechanically inclined enough to do it yourself find someone that is.

 

[adamg]

Can a person tell it has happened to their sled by pulling the QD belt and trying to wiggle the upper sprocket?

 

[LoudHandle]

Can a person tell it has happened to their sled by pulling the QD belt and trying to wiggle the upper sprocket?

That will give you and indication of good or needs further investigation. As will grabbing the brake disk and checking for any movement. But if it moves you are likely already too late to save the current parts.

The first thing I look at:
Is the upper bearing plate seated against the tunnel? Then, is the inner bearing race seated to the shoulder on the Jackshaft? Check for any play in the brake disk or movement of top sprocket? If those three things check out? Then verify bolt torque. I would also check the PTO side driveshaft to driveshaft bearing fitment. Seems they are not a press fit, as they should be. This fit is also susceptible to degradation and in as little as 500 miles can be more than 1/16th undersized. When you have your side panel off check for a gap between the stub and the inner bearing race, towards the front of the sled as the track will be pulling it towards the rear. Any gap is too much, get it warranted and Loctite the new shaft bearing in place.

Hope this is helpful and keeps you from being towed home.

 

[Scott]

Can a person tell it has happened to their sled by pulling the QD belt and trying to wiggle the upper sprocket?

YES!!! Pull the upper pulley bolt and you will know almost instantly.

 

[rmscustom]

IMO hot-top-pulley-itis is simply chassis blue printing combined with the flexy QD plate.

I had the "itis" in all riding conditions, even though I kept my top pulley tight. My QD belt always rode against the top pulley flange too.
When I had my top pulley off, I noticed i needed to push in a lot (50 thouish) to get the top bearing to contact the flange on the jackshaft. So, when torqued up, the bearing was in a side load condition and the pulleys were misaligned.
I placed the correct shim on the jackshaft so when untorqued the shaft just contacted the upper bearing (did not push out on bearing and did not require push in to contact).
Torqued things up and since then, the "itis" is gone and the QD belt finds it's own center between the upper pulley quide flange and the lower pulley guide flange.
Still have excessive heat after long wide open stuff but it's coming from the muffler because everything (belt, both pulleys, and brake) is hot.

Been trying to break the '13 belt the last few rides in spring conditions so I can use the unreturnable-for-me. spare I have. No luck so far lol. 1700 miles and growing. I'll probably use it next season til it breaks just because.

Why is this more important than on a chaincase like before? I'm sure many Pros were not perfect from the factory (like any other brand) in chassis alignment. Bearings can take quite a bit of sideload before failure.
The big difference is a multi-plate chain has a built in tolerance for mis-alignment. It is flexy when new and flexier when worn. It is also narrower.
The wide rigid belt needs to be closer to perfect alignment especially with the flange to flange guide system that Poo used. If your going to align your pulleys you might as well do it from the jackshaft side to take off the side load on the bearing too.

I just completed what I'll call the Geo mod (as he recommened it months ago on here) to a '13 QD PRO. Here are my observations on this sled and what worked for me.

After looking it over the QD looked good, bearing plate tight to chassis everywhere and bearing was pinched as intended. What we did find was the driveshaft bearing on the clutch side that should be a press fit was already worn more than a sixteenth undersized in 472 miles.

After disassembly, removed rear suspension, battery, driven clutch, drive shaft, QD belt and sprocket, brake caliper and disk. I drilled the two top rivets out thru the QD plate (you can see the two raised spots on the QDBearing plate casting to give them clearance for the rivet head). Once you have the pilot in the QD plate and the rivet gone except the flange ring, drill plate again to 5/16". Then from inside the tunnel drill the rivet holes out to 5/16" also. You should just have the rivet flange left. Rather than pry the nicely glued QD plate (in this case) away and re-gluing it, I took a very small flat blade screw driver and deformed the rivet flange on opposite sides and it then falls thru the drilled hole. Since the QD plate on this sled was tight to the tunnel we elected to not add glue and just add the two shortened (11/16" long) Torx drive chassis bolts and bolted the upper plate to the tunnel with chassis nylock nuts. Note the front rib interferes slightly so we removed enough of the rib for the bolt head to sit flat. The shortened bolts and nuts are in the top corner of the tunnel and do not interfere with track clearances. We then reassembled with a new driveshaft with the HappyFace collar glued on and we Loctited the bearing on the other side to hopefully avoid it failing in the next 500 miles.

Note, this sled was owned by a dealership owner and still had obvious flaws. The QD side was as good as I've seen, but the lower clutch bearing shaft to bearing clearances on the shafts need to be checked and appear loose on the shafts I have had my hands on. From that I would recommend Checking them before they wear enough to shear off and getting them warrantied. Loctiting the bearing in place on the new shaft to prolong the life of the shaft.

Hope you find this helpful.

TTT,
You guys are spot on... Had some time tonight and pulled my QD sprockets, caliper and disc off and noticed I had to push my plate in to get the top bearing to contact the flange on the jackshaft, same as Geo found. I think what saved me is I put a 12 driveshaft in before I rode it and torqued the QD bolts more than the recommended 30ft lbs from day one and checked every few rides. Still on original belt.

Geo, did you make the shims or buy them?

And while I'm in there I want to replace the bearings, is there a better bearing available?

 

[LoudHandle]

TTT,
You guys are spot on... Had some time tonight and pulled my QD sprockets, caliper and disc off and noticed I had to push my plate in to get the top bearing to contact the flange on the jackshaft, same as Geo found. I think what saved me is I put a 12 driveshaft in before I rode it and torqued the QD bolts more than the recommended 30ft lbs from day one and checked every few rides. Still on original belt.

Geo, did you make the shims or buy them?

And while I'm in there I want to replace the bearings, is there a better bearing available?

Glad you found the information useful;

The one that I wrote the post about did not need any shimming once the top of the QD plate was bolted as described in my post. I'm pretty sure I read in another of Geo's posts that he owns or has access to a lathe and made his own shims as well as trued some metal off the break hub to increase the surface area available to the pinch the bearing race. (again from my memory, and may not have it word for word, and I don't want to speak for him) but thought I would try and answer your questions.

The factory bearings are NTN, which are pretty near top of the line with out shelling out the coin for hybrid ceramic or other exotic, spendy units. However the NTN blue sealed bearings come pre-packed with Avlina 2 (spelling?) arctic grade grease which would be my preference of what is available off the shelf. You can get them from High Performance Engineering, Dennis Kirk and other discount houses as well as your local bearing supplier for the same or cheaper than the stock Polaris bearings with their markup.

 

[rmscustom]

Thanks LH, I'm going to bolt it to the tunnel like you described and see what it looks like. QD plate appears to be glued tight so I don't see any reason to take it off.