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Discussion Starter #1
More on early crownwheel bearing degradation due to excess shim thickness:

The history of this FD is unkown, purchased by a forum member off eBay. There was oil leaking at the hub seal but no other indications of FD failure.

Findings:
Existing shim was 0.8mm (of all the drives I've rebuilt, I've removed many 0.7, 0.8m and even the occasional 1.0mm shim. I've never had my measurements call for more than a 0.7mm shim.)

In this case, the new bearing called for 0.50mm shim thickness. That suggests that this FD had 0.3mm excess preload.

The original bearing seemed fine, but past experience told me to cut it open. Sure enough, wear of the outer race groove was clearly evident. I used a pencil to drag the pencil lead across the edge of the groove in a couple of different places to show how the groove is worn to a sharp edge in some areas, but much smoother in other areas. The sharp edged area shaves the pencil lead, the smoother area just leaves a normal pencil tracing across the edge of the groove.
I speculate that this wallowing out of the bearing race results in just enough axial runout of the wheel to cause a weeping of lube at the seal, but otherwise is unnoticed. The bearing turns smoothly and there are no shiney flakes of metal on the drain plug. I suspect that there may have been increasing grey fuzz on the drain plug but that history is not available to me.
 

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I think that's verrrryyyy intteresting, and I also think it's very cool that you're willing to do a pre-emptive rebuild of these bad boys for a reasonable price! :thumb::thumb:
 

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You are the MAN Curtis. I can't imagine a dealer taking the time to look into the thing that deep and do the research that you have been doing. Keep up the good work :dance:
 

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2005 K1200LT
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I'll be doing a post mortem on whdunn4's rear drive this weekend. I am heading up to Lebanon, TN Saturday morning to install my loaner drive so Wes can fly in and ride her home to PA. I'll carry his old drive home for a re-build. Even going up on the LT with the tools in the Bushtec. Weather is just to good to take the car.
 

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Way to go John! :)

John
jzeiler said:
I'll be doing a post mortem on whdunn4's rear drive this weekend. I am heading up to Lebanon, TN Saturday morning to install my loaner drive so Wes can fly in and ride her home to PA. I'll carry his old drive home for a re-build. Even going up on the LT with the tools in the Bushtec. Weather is just to good to take the car.
 

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jzeiler said:
I'll be doing a post mortem on whdunn4's rear drive this weekend. I am heading up to Lebanon, TN Saturday morning to install my loaner drive so Wes can fly in and ride her home to PA. I'll carry his old drive home for a re-build. Even going up on the LT with the tools in the Bushtec. Weather is just to good to take the car.
Wow, that is just plain AWESOME. :dance:
 

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2005 K1200LT
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Wes is on his way to the BRP enroute to home. My hat is off to the great people at Steel Riders Cycle in Lebanon, TN. Although all of the other bikes in the shop were of american heritage they graciously allowed Wes to store his bike there for a several days AND offered up the use of a lift to swap out the rear drives. I was ready to wallow in the drive way but it was sure nice to have a lift.

His failure was a classic, big crown wheel bearing. The cage had just shreaded the seal but no wobble on the wheel before removal. Yes there was a thick and a thin shim. Guess I need to start stocking bearings and seals.

Jean even rode up with me and we brought her colapsable rocking chair in the Bushtec. She was happy to sit and read while Wes and I wrenched. Should have brought a bottle of wine and a block of cheese, could have had a picinick. Weather was a balmy 63 degrees so nice after a summer in the high 90's.
 

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Discussion Starter #8
jzeiler said:
Wes is on his way to the BRP enroute to home. My hat is off to the great people at Steel Riders Cycle in Lebanon, TN. Although all of the other bikes in the shop were of american heritage they graciously allowed Wes to store his bike there for a several days AND offered up the use of a lift to swap out the rear drives. I was ready to wallow in the drive way but it was sure nice to have a lift.

His failure was a classic, big crown wheel bearing. The cage had just shreaded the seal but no wobble on the wheel before removal. Yes there was a thick and a thin shim. Guess I need to start stocking bearings and seals.

Jean even rode up with me and we brought her colapsable rocking chair in the Bushtec. She was happy to sit and read while Wes and I wrenched. Should have brought a bottle of wine and a block of cheese, could have had a picinick. Weather was a balmy 63 degrees so nice after a summer in the high 90's.
John,
You sure set the standard for being willing to go the distance to help a rider.

I'll be curious to know the thickness of the existing shims, and what the new bearing ends up calling for.
 

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2005 K1200LT
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I'll let you know Curtis. I just ordered (two this time so I'll have one in sock) the bearing and seal. This one also had a bit of oil in the pinion area so I will replace that seal as well. No needle bearing sleeve creep on this one. This one only had 15,500 miles on the entire bike (02)!!
 

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Discussion Starter #10
jzeiler said:
I'll let you know Curtis. I just ordered (two this time so I'll have one in sock) the bearing and seal. This one also had a bit of oil in the pinion area so I will replace that seal as well. No needle bearing sleeve creep on this one. This one only had 15,500 miles on the entire bike (02)!!
Thanks John, l continue to try to add to what I think I know about these FD failures.
15.5Kmiles, wow.... early failure!

In cases of input pinion leaks, I am as suspicious of the sealant at the threads of the locking ring as I am suspicious of the seal itself. I've taken a couple apart where it really looked like the sealant around the threads of the locking ring was incomplete and lube was seeping through there. When I rebuild those, I try to ensure the threads are really clean inside the FD housing and on the locking ring. Then I make sure the locking ring threads are fully coated with Hylomar.
Rebuilding that input pinion is kind of a pain in the neck, you can have 'em. :) At least with just changing the seal, you don't have to remove and replace the pinion shaft assembly.

Best Regards
 
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