Replacement Top Gear Bushing

[twyztid]

I am wondering if the GGB (Garlock) DP31 series would hold up longer. It has a much higher pU factor value than the stock-type DU series.

DP31 series specs

Stock-type DU series specs

Steady Load comparison

 

[ClutchMaster]

I am wondering if the GGB (Garlock) DP31 series would hold up longer. It has a much higher pU factor value than the stock-type DU series.

DP31 series specs
View attachment 148830

Stock-type DU series specs
View attachment 148831

Steady Load comparison
View attachment 148832

Probably not, the static rating is exactly the same. The bearing isn’t worn from rotational friction. It gets hammered out of shape. That doesn’t mean it won’t hold up better tho, give it a try.

 

[twyztid]

Probably not, the static rating is exactly the same. The bearing isn’t worn from rotational friction. It gets hammered out of shape. That doesn’t mean it won’t hold up better tho, give it a try.

Working on locating a place that I can get a quote from. The DP31 series are not as readily available to purchase as the DU series.

 

[Big_Phil]

Ever look at them? What kind of wear? I will admit it's entirely possible even when wore there might not be a issue. Most of us that have seen the case blow ups just don't want to take the chance. Heck one look at the tiny teeth that have to line up perfectly with other gear and drive the sled is enough to know its not worth chancing.

I last had mine apart at 9000kms or so, it was just as tight as a new gear so I left the stock one in there.

 

[Big_Phil]

The chain changed, used to be a silent chain now it’s a HYVO.

He has the same chain and gear as my 17 sidewinder has. No oil holes in the top gear on either.

 

[ClutchMaster]

I wonder what was changed on these over the years. 11000+ kms on mine and I am definitely not easy on things. My buddy has a high mile 1100 Cat, has like 25000kms or so on his 21 top gear, he bought one of the update kits with a new jackshaft back in 2015 or so.

The old Cat 1100t’s has a silent chain. Also had an auto tensioner that over tightened the chain causing failures.
I’m wondering if some of the chains were manufactured with the pitch being off somewhat. This would explain the random issues with the bushing failures. I’m still leaning twards over tight chain causing the issues, thus the reason why yamaha specs it so loose. Chain climbing on the gears due to worn or incorrect pitch would cause exponential load on the upper bushing, three times the actual pulling force of the chain.
It’s not the oil hole because some have zero wear with no holes at all.

 

[Big_Phil]

The old Cat 1100t’s has a silent chain. Also had an auto tensioner that over tightened the chain causing failures.
I’m wondering if some of the chains were manufactured with the pitch being off somewhat. This would explain the random issues with the bushing failures. I’m still leaning twards over tight chain causing the issues, thus the reason why yamaha specs it so loose. Chain climbing on the gears due to worn or incorrect pitch would cause exponential load on the upper bushing, three times the actual pulling force of the chain.
It’s not the oil hole because some have zero wear with no holes at all.

My buddies with 1100 cats no longer run the stock chain and auto tensioner. There is/was an update kit that came out for the cats in 2014 or 2015 that is the same chain and top gear setup that the sidewinder uses. 21/41 gearing. I run mine chain tighter than spec and have been since I've had the sled. Its obviously just a quality control problem somewhere along the line, because some are fine and some are not fine and there does not seem to be any reason why some fail and some do not fail. If a chain and gear was going to fail, mine would have by now it seems. I had it out loaded with chisels the last days of the year this season and must have done 100 anti lag launches with dead hook. I also run Mercruiser high performance outdrive oil in my chain case, but I cant see that being the reason why it lasts longer, should be the same as any other chaincase lube you would think.

 

[ClutchMaster]

I’m leaning twards chain pitch inconsistencies
Mine did it when it was brand new

 

[Big_Phil]

I’m leaning twards chain pitch inconsistencies
Mine did it when it was brand new

That would make perfect sense. Is your sled good now with a new chain? It seems that people who only change the top gear and not the chain keep having the bushing fail no matter what.

 

[cannondale27]

#1 Rate of actual failure is very low. By failure I mean bushing wore down to the steel and galling the shaft. That what I saw a lot on the 12/13 cats along with gears that were all chewed up.
When I replace mine every year at 3-5000mi there is still some coating left usually on half of bushing. The wear at that point is about .003in. Maybe would go another year or more but not taking a chance with everything relying on those little teeth meshing.

 

[ClutchMaster]

That would make perfect sense. Is your sled good now with a new chain? It seems that people who only change the top gear and not the chain keep having the bushing fail no matter what.

Yea it’s good now with the new chain and loose tensioner setting. Before with a tight chain I was eating bushings in under 2k miles.

 

[1nc 2000]

#1 Rate of actual failure is very low. By failure I mean bushing wore down to the steel and galling the shaft. That what I saw a lot on the 12/13 cats along with gears that were all chewed up.
When I replace mine every year at 3-5000mi there is still some coating left usually on half of bushing. The wear at that point is about .003in. Maybe would go another year or more but not taking a chance with everything relying on those little teeth meshing.

Failure for mine is when I shifted it into reverse and it would not shift into fwd, even with a new actuator installed. Had to remove actuator and manually shift into fwd to drive back home.
Had to finish out the season with no reverse.

 

[STAIN]

Yea it’s good now with the new chain and loose tensioner setting. Before with a tight chain I was eating bushings in under 2k miles.

What gear/chain combo are you running?

 

[NYTurbo]

That would make perfect sense. Is your sled good now with a new chain? It seems that people who only change the top gear and not the chain keep having the bushing fail no matter what.

There is a large group of us in the area with 998s from 2017s to 2019s. We have all gone through bushings but since we swapped to better bushing the issue has so far gone away. Many with 3000 plus on the bushing and is still as snug as the day it was installed. Another year will really tell the story but if we can get a season on a bushing I'm good with that, just change it out at a gear lube change. None of us have changed chains, and we've put lots of passes on race fuel and trail ride at 280 plus .

 

[cannondale27]

There is a large group of us in the area with 998s from 2017s to 2019s. We have all gone through bushings but since we swapped to better bushing the issue has so far gone away. Many with 3000 plus on the bushing and is still as snug as the day it was installed. Another year will really tell the story but if we can get a season on a bushing I'm good with that, just change it out at a gear lube change. None of us have changed chains, and we've put lots of passes on race fuel and trail ride at 280 plus .

Just to be clear the better bushing you guys are using is the one Clutchmaster posted from McMaster Carr?