Oil holes in top gears - gone!

[Turboflash]

FYI- I was just informed by Country Cat that Arctic Cat top hyvo gears no longer have oil holes. Maybe this is old news to some. Country Cat says Cat upgraded the bushing material and the oil holes are no longer needed. There is likely still some inventory out there of the earlier gears with holes.

 

[REDLINE 1]

FYI- I was just informed by Country Cat that Arctic Cat top hyvo gears no longer have oil holes. Maybe this is old news to some. Country Cat says Cat upgraded the bushing material and the oil holes are no longer needed. There is likely still some inventory out there of the earlier gears with holes.

I wonder if they are necessary? Doesn’t that gear spend most of its life locked to the shaft? Only spins on the shaft when in reverse?

 

[Turboflash]

Yes. That is correct. Gear only turns on shaft when sled is in reverse.
There's many pages of discussion on this subject (going back to 2017) on this forum for those who want to catch up on the whole subject.

 

[REDLINE 1]

My Scott Taylor gear does have the oil holes so when I installed the Prevost bushing I did drill the holes threw I figured it wouldn’t hurt

 

[Srxspec]

The stock bushing still sucks, even in 2026 models!

 

[KnappAttack]

Just put a Hurricane roller bearing in and be done with the entire problem with bushings if looking for bulletproofing the top gear.

 

[twyztid]

IMO those oil holes were their failed attempt to fix the problem. The real problem is that the type of bushing that they use can't handle the shock load (which "pushes" the teflon off the bronze liner). It is not a lubrication problem. They should have never used that type of bushing in the first place.

This is also the reason that, although it seems to be working for a number of people, the roller bearing that Hurricane sells is not really the right thing for this application either.

 

[Turboflash]

This subject has been discussed at length in our forum.
I've said it before - and I'm not wanting to start an argument, but IMO, there's more at play with the problem than just lubrication and/or wrong bushing material.
By that I mean harmonics/resonance. There's really no other way to explain bushings that failed after only a couple hundred miles on a brand new stock sled.
And, the vast majority of the failures (90%?) have been in Sidewinders, not Thundercats. Why?
1. Sidewinder stock gearing is different (21/41) vs. Cat (24/50). This means weight of gearing and chain is lower in Sidewinder (gears are smaller, chain is shorter).
2. Sidewinder jackshaft is different on secondary end due to Yamaha clutches. Weight of jackshaft is different vs Cat.
3. Yamaha primary vs Team or ADAPT. Weight of clutches are different.
4. Belt is different length & width, therefore slightly different.
It would have to proven in scientifically, but in my opinion, the differences in component weights, along with differences in jackshaft design contribute to destructive resonance/harmonics in the jackshaft (a "buzzing") which destroys the bushing. The mystery is why some Winders have no issue but others can have a failed bushing in not many miles/hours. Why only relatively few Cats experience an issue but majority don't?
I think there's no doubt it's another snafu by Cat engineering - wrong material, wrong design, etc. It continues to this day.

 

[sideshowBob]

This subject has been discussed at length in our forum.
I've said it before - and I'm not wanting to start an argument, but IMO, there's more at play with the problem than just lubrication and/or wrong bushing material.
By that I mean harmonics/resonance. There's really no other way to explain bushings that failed after only a couple hundred miles on a brand new stock sled.
And, the vast majority of the failures (90%?) have been in Sidewinders, not Thundercats. Why?
1. Sidewinder stock gearing is different (21/41) vs. Cat (24/50). This means weight of gearing and chain is lower in Sidewinder (gears are smaller, chain is shorter).
2. Sidewinder jackshaft is different on secondary end due to Yamaha clutches. Weight of jackshaft is different vs Cat.
3. Yamaha primary vs Team or ADAPT. Weight of clutches are different.
4. Belt is different length & width, therefore slightly different.
It would have to proven in scientifically, but in my opinion, the differences in component weights, along with differences in jackshaft design contribute to destructive resonance/harmonics in the jackshaft (a "buzzing") which destroys the bushing. The mystery is why some Winders have no issue but others can have a failed bushing in not many miles/hours. Why only relatively few Cats experience an issue but majority don't?
I think there's no doubt it's another snafu by Cat engineering - wrong material, wrong design, etc. It continues to this day.

I agree with this especially when it comes to the smaller gears on the typical sidewinder. The bushing wear I have seen on some of the SW 21 tooth top gears has had the appearance of damage caused by chattering or pitting of the bushing material not of friction wear.
I run 26/45 gears on my XTX with its 8 x 3" drivers for many 1000s of miles and I had not experienced excessive bushing wear prior to installing the DMC bushing.