Replacement Top Gear Bushing

[NYTurbo]

Gears, chain, tensioner, jackshaft, bearings all changed. Used to be able to buy bushing from Cat , can't any longer. Plus a lot of people are running 270 plus horsepower mile after mile

 

[twyztid]

McMaster #60695k7
Is identical makeup as the stock bushing it will need to be trimmed 1/8” to fit.
Cost is under $5

It actually has 500lbs less load capacity than a 660 bronze bearing but slightly more than the oilight bronze bushings.

The beginning of the week I will post the pages from both GGB Bearing & Bunting Bearings showing that the stock type bushings have multiple times more load capacity than an SAE660 cast bronze bushing. I do not know what brand McMastet-Carr sells, but I suppose I could ask them. We order from them frequently at work.

 

[ClutchMaster]

The beginning of the week I will post the pages from both GGB Bearing & Bunting Bearings showing that the stock type bushings have multiple times more load capacity than an SAE660 cast bronze bushing. I do not know what brand McMastet-Carr sells, but I suppose I could ask them. We order from them frequently at work.

The bearing I listed is steel shell, sintered bronze with PTFE lining. Exactly the same makeup as the stock bushing.

It really doesn’t matter to me I’m not having issues anymore. I will forego telling my story as I will just be accused of lying, so have fun figuring it out. Yes it’s true, some have no issues, even at 300hp.

 

[cannondale27]

The bearing I listed is steel shell, sintered bronze with PTFE lining. Exactly the same makeup as the stock bushing.

It really doesn’t matter to me I’m not having issues anymore. I will forego telling my story as I will just be accused of lying, so have fun figuring it out. Yes it’s true, some have no issues, even at 300hp.

Never said you lied. I believe you but I think you need to check it again since many factors could increase wear. Maybe it takes a bunch of times reversing and you didn’t this round. All I know is mine has always wore in one season of 3-5000mi. No matter what chain tension I ran.

 

[NYTurbo]

Put a quality bushing in a gear and take a brand new gear , compare the fit on the shaft you'll see why they wear, and I assume some OEM gears are better than others hence why people report that the bushing is lasting longer than others. I'm sure a better quality oil , filling above the sight glass and chain tension all contribute to longevity but IMHO the stock bushings are just very low quality. Some 2019s lasted all of 300km last year .

 

[ClutchMaster]

I think it has to do more with the chain wearing/stretching causing a climb issue.
http://chain-guide.com/basics/2-2-1-chordal-action.html

 

[ClutchMaster]

Only things I changed were running looser and I had a new chain.

 

[krm]

Just add more gear lube to the case as the factory amount isn't enough .

 

[twyztid]

The bearing I listed is steel shell, sintered bronze with PTFE lining. Exactly the same makeup as the stock bushing.

It really doesn’t matter to me I’m not having issues anymore. I will forego telling my story as I will just be accused of lying, so have fun figuring it out. Yes it’s true, some have no issues, even at 300hp.

I was just saying that based on my research, the stock-type bushing has higher load capacity than a cast bronze bushing. McMaster-Carr may be listing a different value than what is shown in the links below. The "P Value" is the load capacity. The "PV Value" is the load capacity at the max rotational speed. The cast bronze has a higher P value but lower PV value than the stock type-bushing. Since the gear only spins on the shaft in reverse, I would think the P value would be more important than the PV value.

Cast Bronze Bushing
https://catalog.buntingbearings.com...c93200-sae-660-sleeve-plain-bearings/cb161808

Stock-type Bushing
https://catalog.buntingbearings.com...ricant-bearings-inch-sizes/16bu16?plpver=1004

 

[ClutchMaster]

I was just saying that based on my research, the stock-type bushing has higher load capacity than a cast bronze bushing. McMaster-Carr may be listing a different value than what is shown in the links below. The "P Value" is the load capacity. The "PV Value" is the load capacity at the max rotational speed. The cast bronze has a higher P value but lower PV value than the stock type-bushing. Since the gear only spins on the shaft in reverse, I would think the P value would be more important than the PV value.

Cast Bronze Bushing
https://catalog.buntingbearings.com...c93200-sae-660-sleeve-plain-bearings/cb161808

Stock-type Bushing
https://catalog.buntingbearings.com...ricant-bearings-inch-sizes/16bu16?plpver=1004

I’m not referring to the cast bronze bushing, if you want to save some coin this bushing is the same composition as the stock bushing. Trim the length of the bushing and use this one.
I press them in and trim with a hack saw then file smooth. 60695k7

 

[Allan]

I used the this bushing skf pcz 1616E on my Viper when I did my service this year. Will see how it hold up next year. I had to cut a little off the bushing.

https://www.skf.com/group/products/...le-bushings/index.html?designation=PCZ 1616 E

 

[NYTurbo]

I’m not referring to the cast bronze bushing, if you want to save some coin this bushing is the same composition as the stock bushing. Trim the length of the bushing and use this one.
I press them in and trim with a hack saw then file


The bearing you posted is not the the same composition but is a much better choice .

 

[cannondale27]

What’s better? Maybe that’s why Clutchmaster is not seeing wear? That would be great! I will give it a try.

Cutchmaster have you ever worn this exact bushing? Not stock and not the bronze type.

 

[ClutchMaster]

What’s better? Maybe that’s why Clutchmaster is not seeing wear? That would be great! I will give it a try.

Cutchmaster have you ever worn this exact bushing? Not stock and not the bronze type.

I used a new upper gear last year with the stock bushing and three oil holes and new chain. I did however give one to a my friend Glen and he said it works and looks identical to the stock one, no resizing the bore diameter, fits nicely. I didn’t even put one in the end of this season because the original was in perfect shape.

 

[twyztid]

I contacted McMaster-Carr and this was their response.

Hi Kevin,

Theses bearings (60695K7) are manufactured specifically for us by Beemer Precision; therefore, their part number is also 60695K7.
They are not listed on the Beemer Precision website, but you can reply to this email with your performance questions and we'll get back to you with the available information.

Andy

Notice on both of the spec sheets below that they have Very Good listed for running these bushings dry. That is due to the Teflon layer. I realize that a lot of people thing the wear on this bushing is at least partially due to an oiling issue (hence the oil holes in the newer ones). I do not believe this is true... especially with the small amount of time that the bushing actually spins on the shaft.


Here is the spec sheet McMaster-Carr sent me for the #60695K7 bushing.

This is the spec sheet for the GGB DU series bushings (which is supposedly the manufacturer of the OEM ones in the gears). It appears that this data sheet has the static & dynamic ratings backwards since the 20000 & 36000 are flipped. Notice the metric ratings listed to the right. The static rating is higher.