Transmission main shaft
#21
I'm in the middle of replacing the bearing in question. I firmly believe that the bearing design and manufacture itself is sound. Otherwise ALL 07's would have the issue. In fact, all Harley's with a 6 speed would be spitting out bad bearings. That's just not the case though. Yes the incidence of 07 failures seems high, but I believe it's something else that's causing it. Perhaps bad bore alignment? Bad true in the mainshaft? Who know's?
I have the F.A.G US headquarters within a few miles of my house. I think I'll give them a call and see if I can shed some light on this problem.
BTW - the plastic ball seperators (for lack of proper terminology) are only there to align the ***** and distribute the loads. They are NOT plastic bearings.
I have the F.A.G US headquarters within a few miles of my house. I think I'll give them a call and see if I can shed some light on this problem.
BTW - the plastic ball seperators (for lack of proper terminology) are only there to align the ***** and distribute the loads. They are NOT plastic bearings.
My bike started whining during a trip to TX in May 2008. Before the trip I adjusted my belt according to the book only slightly looser, but once the trip was underway I noticed the belt was very tight once warmed up--way tighter than I was comfortable with. I didn't have the tools to adjust so I let it go 'til I returned home. Instead of the 1/4" spec for SG's I used 3/8" cold before the trip, the minimum for EG's since I was using a shock height midway between the two models (12½"). My tech and I have a theory that the belt tension put extra strain on the output-shaft bearing and that is what caused the initial damage. Riding it more made it worse and the noise increased as the miles and months progressed. It was a full 16k miles and 18 months before the tranny was repaired, as until that time nobody was sure where the noise originated from. What's more, I didn't blame the tranny until the very last because there was no evidence of a failed bearing--i.e., no metal shavings on the drain magnet. By that time it was loud enough where you could hear the roughness when the bike was jacked up, rotating the rear wheel, and my ear at the front belt pulley. At that time I knew it was the mainshaft bearing and took it in for warranty service.
I hope you're wrong about the line-bore theory, as if this is the cause we who have had the problem may be destined to have it every couple of years for the duration. However, it makes me feel good to think maybe the belt tension was to blame. Since that time I've been setting it looser than even the EG spec, around 1/2" cold using the 10# method. This is where I set it for my old RK which I rode for >100k miles and never changed the belt.
Please forward any info you get in your talk with F.A.G.
Last edited by iclick; 08-23-2010 at 11:26 AM.
#22
??????????????
Can someone tell me what bearing that you are talking about. What I consider the bearing that actually supports the front pulley for the drive belt is the inner primary bearing. Held by a snap ring in the inner primary case. There is an inner race for this bearing pressed on the main drive gear that the drive pulley is splined to. This bearing is lubricated my the primary fluid. In one post someone is talking about transmission fluid. My Harley has the old manual primary adjuster and I have enough run out to go from max to minimum on the chain slop. Starting to wonder maybe the rear bearing is worn enough to cause this problem. I have a lot of noise coming from somewhere in the primary. Is there a way to check a run out for this bearing or is a teardown required?
#23
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Iclick, Yes I agree that the excess stress of over tightening the belt could effect the bearings - mainly the 5th gear output bearing and the inner primary. But thinking about this scenario, you'd think the smaller primary bearing would go first?
Here's another theory based on miss alignment of bores, and where your theory actually helps to prove.
The Mainshaft turns on 5 bearings (trap door, 5th gear bearing, 2 mainshaft bearings (inside 5th gear), primary inner bearing). Take the 2 mainshaft bearings out of the equation, since they effectively turn the mainshaft and 5th gear into a single unit (ideally).
Now envision, 3 bores on a centerline from the trap door through the trans case left and into the primary inner. If one of those are out of alignment by a small fraction, the stress would eventually wear one of them out (at the least). My guess is that the miss-alignment occurs when the inner primary is installed to the engine and trans. Since the only alignment features between the three bores are the rolled dowel pins, there could potentially be enough room for our miss alignment.
I've heard since I was a youngster, that you should always avoid 3 bearings on the same shaft, presumably for this reason.
While we're contemplating this stuff, I've contacted someone at F.A.G. and he's looking into it.
I'll relay his thoughts when I get them.
Here's another theory based on miss alignment of bores, and where your theory actually helps to prove.
The Mainshaft turns on 5 bearings (trap door, 5th gear bearing, 2 mainshaft bearings (inside 5th gear), primary inner bearing). Take the 2 mainshaft bearings out of the equation, since they effectively turn the mainshaft and 5th gear into a single unit (ideally).
Now envision, 3 bores on a centerline from the trap door through the trans case left and into the primary inner. If one of those are out of alignment by a small fraction, the stress would eventually wear one of them out (at the least). My guess is that the miss-alignment occurs when the inner primary is installed to the engine and trans. Since the only alignment features between the three bores are the rolled dowel pins, there could potentially be enough room for our miss alignment.
I've heard since I was a youngster, that you should always avoid 3 bearings on the same shaft, presumably for this reason.
While we're contemplating this stuff, I've contacted someone at F.A.G. and he's looking into it.
I'll relay his thoughts when I get them.
#24
Join Date: Jun 2008
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Can someone tell me what bearing that you are talking about. What I consider the bearing that actually supports the front pulley for the drive belt is the inner primary bearing. Held by a snap ring in the inner primary case. There is an inner race for this bearing pressed on the main drive gear that the drive pulley is splined to. This bearing is lubricated my the primary fluid. In one post someone is talking about transmission fluid. My Harley has the old manual primary adjuster and I have enough run out to go from max to minimum on the chain slop. Starting to wonder maybe the rear bearing is worn enough to cause this problem. I have a lot of noise coming from somewhere in the primary. Is there a way to check a run out for this bearing or is a teardown required?
If you have a leak, and it's primary oil, the primary seal is easy to replace. However, if the seals bad it's probably because of a bad bearing. The bearing is also easy to replace, once of course you remove and reinstall a new outer race. And FYI, that's a bi-otch to do. Get the right tools.
I cut mine off and will be replacing with a Baker bearing. No need for the inner race then.
Baker click here: http://store.bakerdrivetrain.com/Pro...=189-56&type=4
Last edited by Scorpion07; 08-23-2010 at 01:13 PM.
#25
FWIW they also replaced the "gear assembly, driven output" (#35122-06) on my bike as a precaution.
Here's another theory based on miss alignment of bores, and where your theory actually helps to prove. The Mainshaft turns on 5 bearings (trap door, 5th gear bearing, 2 mainshaft bearings (inside 5th gear), primary inner bearing). Take the 2 mainshaft bearings out of the equation, since they effectively turn the mainshaft and 5th gear into a single unit (ideally). Now envision, 3 bores on a centerline from the trap door through the trans case left and into the primary inner. If one of those are out of alignment by a small fraction, the stress would eventually wear one of them out (at the least). My guess is that the miss-alignment occurs when the inner primary is installed to the engine and trans. Since the only alignment features between the three bores are the rolled dowel pins, there could potentially be enough room for our miss alignment.
I've heard since I was a youngster, that you should always avoid 3 bearings on the same shaft, presumably for this reason.
I've heard since I was a youngster, that you should always avoid 3 bearings on the same shaft, presumably for this reason.
While we're contemplating this stuff, I've contacted someone at F.A.G. and he's looking into it. I'll relay his thoughts when I get them.
Last edited by iclick; 08-23-2010 at 12:35 PM.
#27
There are actually two bearings that support the drive pulley. One the inner primary, and the other supporting the 5th gear on the mainshaft in the left side of the trans housing.
If you have a leak, and it's primary oil, the primary seal is easy to replace. However, if the seals bad it's probably because of a bad bearing. The bearing is also easy to replace, once of course you remove and reinstall a new outer race. And FYI, that's a bi-otch to do. Get the right tools.
I cut mine off and will be replacing with a Baker bearing. No need for the inner race then.
Baker click here: http://store.bakerdrivetrain.com/Pro...=189-56&type=4
If you have a leak, and it's primary oil, the primary seal is easy to replace. However, if the seals bad it's probably because of a bad bearing. The bearing is also easy to replace, once of course you remove and reinstall a new outer race. And FYI, that's a bi-otch to do. Get the right tools.
I cut mine off and will be replacing with a Baker bearing. No need for the inner race then.
Baker click here: http://store.bakerdrivetrain.com/Pro...=189-56&type=4
#28
IClick . . .
HD made an update to the inner primary (mainshaft) bearing. I believe the early bearings (06 dynas and 07 touring) had faulty (soft) inner bearing races. I also believe that HD knows this and is waiting out the failures without saying anything. Too many have failed at low mileage IMO.
I replaced my inner primary bearing at 20K. The race and bearing were both failing. Here are the threads started at that time.
https://www.hdforums.com/forum/touri...only-help.html
This thread shows that there was an update to the mainshaft and bearing in late 07, early 08. My 07 had the updated bearing and when I ordered the bearing from the 07 parts book, it was the wrong bearing. I did some research and came up with the updated bearing.
https://www.hdforums.com/forum/prima...need-help.html
Curious thing is that my bike had the updated bearing but it still failed early.
I actually kept my belt slightly looser that spec so I doubt that was a factor. I do ride 2up all the time and we are often loaded with gear. I wonder if the added weight causes the belt to run tighter.
What do you think??????? Anyone????
HD made an update to the inner primary (mainshaft) bearing. I believe the early bearings (06 dynas and 07 touring) had faulty (soft) inner bearing races. I also believe that HD knows this and is waiting out the failures without saying anything. Too many have failed at low mileage IMO.
I replaced my inner primary bearing at 20K. The race and bearing were both failing. Here are the threads started at that time.
https://www.hdforums.com/forum/touri...only-help.html
This thread shows that there was an update to the mainshaft and bearing in late 07, early 08. My 07 had the updated bearing and when I ordered the bearing from the 07 parts book, it was the wrong bearing. I did some research and came up with the updated bearing.
https://www.hdforums.com/forum/prima...need-help.html
Curious thing is that my bike had the updated bearing but it still failed early.
I actually kept my belt slightly looser that spec so I doubt that was a factor. I do ride 2up all the time and we are often loaded with gear. I wonder if the added weight causes the belt to run tighter.
What do you think??????? Anyone????
Last edited by sifularson; 08-23-2010 at 08:40 PM.
#29
Steve
#30
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I assume Harley designed there bearing for ease of assembly and disassembly of the inner primary cover by not locking the inner race to the bearing. Appears that by using the Baker bearing it no longer needs the primary lube. Is it a sealed bearing? Since its held in inner primary cover by a snap ring is it a tight fit on the main drive gear shaft?
I tried calling earlier today but couldn't get a person. I'll try again tomorrow.