upper gear bushing

[cannondale27]

My Scott Taylor bushing only lasted one season just like stock and costed more than a whole stock cheap gear which is reason I have been buying a stock gear and reusing the bushing since. 5 years 5 bushings. Takes ten minutes at most to push it out and replace.

 

[MrSled]

My Scott Taylor bushing only lasted one season just like stock and costed more than a whole stock cheap gear which is reason I have been buying a stock gear and reusing the bushing since. 5 years 5 bushings. Takes ten minutes at most to push it out and replace.
View attachment 147539

I heard Ulmer is selling a new oillite busing for the top gear.

 

[cannondale27]

I heard Ulmer is selling a new oillite busing for the top gear.

That would be better than stock for sure. Anyone test it?

 

[MrSled]

I heard Ulmer is selling a new oillite busing for the top gear.

Not that I’m aware. Kevin at Port Yamaha told me about it.

 

[RAMSOMAIR]

Lets get some feedback on the Ulmer bushing on here!!

 

[MrSled]

@Srxspec needs to reply.

 

[Turboflash]

I posted this last week, sorta just my theory.....
https://ty4stroke.com/threads/shift-fork-shoes.156975/#post-1479914

Rockerdan Quote:
As I said in our call....I think chain tension may be the one thing we must stay on top of to help top gear bushing longevity. With your massive race tune power you are putting down, my guess is the chain stretches alot quickly, even though it is Scotts.

I spent alot of time looking at this when open, and just dont understand the 1.5 turns out that is spec'd in the manual. I have used 1 turn out for a season and half, and now have gone to 3/4 turn out after finger tight. I am of the thinking that the chain tensioner(being spring loaded), gets pushed back against the bolt head under hard acceleration, which in turn applies massive force onto that chain and top gear bushing, all at once. The top gear is splined into the reverse gear, but where chain is, the bushing underneath is taking the hit, and this hard hit wears the bushing, which in turn does not allow for easy sliding fork motion when going into reverse. The more the bushing wears, the harder it becomes to go into reverse/forward and therefore plastic shoes wear/break.

I feel that with a normal tension back off....that chain does not take as much of a hard hit(when hitting the bolt) under hard acceleration, as its tighter to begin with and has little space between tensioner and bolt head. Which in turn would not put so much pressure onto the top gear bushing.

See what Dan H. comes up with on how tight your chain was, how many turns inward can he turn the bolt until its hand tight would go a long way to proving if this may or may not help everyone. I know many sled top gears with/or without oil holes, have great life, while others have short life. I see no rhyme or reason. So Id like to see if those who kept chains tighter may have longer top gear life or not. I think its a viable question to such a poor design we have to deal with.

Dan

I posted this last week, sorta just my theory.....
https://ty4stroke.com/threads/shift-fork-shoes.156975/#post-1479914

Rockerdan Quote:
As I said in our call....I think chain tension may be the one thing we must stay on top of to help top gear bushing longevity. With your massive race tune power you are putting down, my guess is the chain stretches alot quickly, even though it is Scotts.

I spent alot of time looking at this when open, and just dont understand the 1.5 turns out that is spec'd in the manual. I have used 1 turn out for a season and half, and now have gone to 3/4 turn out after finger tight. I am of the thinking that the chain tensioner(being spring loaded), gets pushed back against the bolt head under hard acceleration, which in turn applies massive force onto that chain and top gear bushing, all at once. The top gear is splined into the reverse gear, but where chain is, the bushing underneath is taking the hit, and this hard hit wears the bushing, which in turn does not allow for easy sliding fork motion when going into reverse. The more the bushing wears, the harder it becomes to go into reverse/forward and therefore plastic shoes wear/break.

I feel that with a normal tension back off....that chain does not take as much of a hard hit(when hitting the bolt) under hard acceleration, as its tighter to begin with and has little space between tensioner and bolt head. Which in turn would not put so much pressure onto the top gear bushing.

See what Dan H. comes up with on how tight your chain was, how many turns inward can he turn the bolt until its hand tight would go a long way to proving if this may or may not help everyone. I know many sled top gears with/or without oil holes, have great life, while others have short life. I see no rhyme or reason. So Id like to see if those who kept chains tighter may have longer top gear life or not. I think its a viable question to such a poor design we have to deal with.

Dan

Dan,
Actually, under high load (accelerating), the rear of the chain is super tight (remember - the jackshaft is increasing in RPM), the front side where the tensioner is, chain is looser. It's under hard breaking that the front side of the chain is tight (assuming the throttle is allowed to return to closed).
IMO, this busing condition seems to exist to a much higher degree in Sidewinders rather than Cats? If so, question is WHY? What's different? The only thing I can come up with is the Yamaha secondary clutch is different than Team Cat one. Is it possible there is resonance or harmonics going on here? Again, just brain-storming.
I run my 280 tune ZR9000 998 chain at 1.5 turns out from hand tight. When I've had my chaincase apart, that seems to be about right for chain tightness. BTW- based on your nightmare story about the roller screw failure, mine is welded. Thanks!

 

[number1kyster]

It seems there are always more horror stories with Sidewinders vs. the Cat 9000 sleds. I would love to see sales numbers. I still think there are way more Sidewinder's out there compared to the 9000's. I see many more Yamaha's on the trails where I ride.

 

[cannondale27]

It seems there are always more horror stories with Sidewinders vs. the Cat 9000 sleds. I would love to see sales numbers. I still think there are way more Sidewinder's out there compared to the 9000's. I see many more Yamaha's on the trails where I ride.

And we ride more and faster! I go though a set of brake pads every year. So maybe something to that.

 

[ROCKERDAN]

I have run my chain at everything between 1-1.5 turns out and have not seen any difference in wear. Oil level Halfway to over top of sight. No difference at all.

Thanks Cannon...I think we need more guys out there testing there theories. Good to know as you have owned this chaincase far longer then many of us.

Probably doesn't matter what we do, the big power and poor design in general of the reverse does not lend longevity to this bushing. Grrrr

I assume its just the fact the chain pulls down on the inner section of gear where bushing is, and the outer section of gear is splined into the reverse gear, so the outer section is held solidly, while inner section and bushing are wearing, and even with oil holes dont seem to last.

I do hear some lasting longer then others, so I thought it could be a chain tension thing? Still not 100% sure but it also could just be how a guy rides it. Some are balls to wall always and others roll on more, corner to corner riders like me may see shorter bushing life vs. big wide open trail riders. Also could be why Toms race tune 31psi rocket that only runs 1/4 mile at a time was able to hurt even Scott Taylor's.

Dan

 

[ROCKERDAN]

Dan,
Actually, under high load (accelerating), the rear of the chain is super tight (remember - the jackshaft is increasing in RPM), the front side where the tensioner is, chain is looser. It's under hard breaking that the front side of the chain is tight (assuming the throttle is allowed to return to closed).
IMO, this busing condition seems to exist to a much higher degree in Sidewinders rather than Cats? If so, question is WHY? What's different? The only thing I can come up with is the Yamaha secondary clutch is different than Team Cat one. Is it possible there is resonance or harmonics going on here? Again, just brain-storming.
I run my 280 tune ZR9000 998 chain at 1.5 turns out from hand tight. When I've had my chaincase apart, that seems to be about right for chain tightness. BTW- based on your nightmare story about the roller screw failure, mine is welded. Thanks!

Very good info brother....It makes me wonder about engine braking on Cat vs Winder too....I know I have little engine braking, Does the Cat offer more engine braking with their compression(BOSS) secondary? Also the gearing differences may have some input here too?

So maybe guys who run big wide open trails and use brakes much less then me, have longer bushing life? I will certainly be changing mine out this fall.....I ran a 22 last season and back to stock 21 this season, so I have split the total mileage between mine which is why they both are Ok still im guessing.

Dan

 

[ROCKERDAN]

It seems there are always more horror stories with Sidewinders vs. the Cat 9000 sleds. I would love to see sales numbers. I still think there are way more Sidewinder's out there compared to the 9000's. I see many more Yamaha's on the trails where I ride.

I do believe this to be true....I know we see far far more Winders out there then Cats.

Dan

 

[Turboflash]

When I first rode my '17 Cat ZR9000 (Team clutching) I was surprised at how much engine braking there is compared to any other sled I've ridden. After 3700 miles, it's still very noticeable at how much engine braking there is. Riding this one, I don't have to use the brakes nearly as much as all the other sleds I've ridden. It takes getting used to for sure. It's just a personality of the Cat w the Team clutching. I've tried different gearing too. Engine braking didn't seem to change. I ran 22/37 (.595) for a season but went back to 21/38 (.553) due to too many belt issues with the taller gearing.
So questions remains - WHY does top sprocket bushing wear out relatively quickly, seemingly more on Winders than Cats? Since chain cases and shafts are the same, the only thing I can think of is Yam secondary clutch being different than Cat. Still suspect harmonics/resonance differences. Facebook Turbo forum on this subject seems to show this issue particular to Winders. I've haven't seen any Cat guys talking about it. It would be interesting to switch a Winder to Team clutches for a test on this. Find out if the issue goes away? As my pic showed, with 3700 miles, my top sprocket bushing looks like brand new still.

 

[slimjim2525]

I have a new to me 18 STX-DX. 2,600 miles on it, and will be close to 3k before the season ends. Is this the upper drive gear behind the reverse gear? Don't want to sound stupid. Will have my case apart before next season, but once I prep the sled for the year, I DO NOT want to start tearing into stuff. I put on about 5K miles a season, bought this halfway through this season.

 

[Turboflash]

Yes, the main top drive sprocket closest to bearing is my understanding.