Driveshaft Gear Coupling

[HYCLE]

Let me try this again.

The seal and debris has caused the groove in the coupler.

This is a very common problem and on some applications you can just put the seal in deeper into the housing. By positioning the seal on a smooth section of the part the leak is repaired.

Here is a link for a good discription and installation instructions for repairing a worn shaft with a sleeve.

Sleeve

And another link about seals and shafts. Look at "Contact Band" in the Glossary.

Contact Band

 

[Fred W]

So, to get this straight, you guys that found the groove first had a symptom of a weeping seal, right?

If one of you could confirm that the new part has no groove there, it would be good so the rest of us will know that if the seal isn't weeping there is no real reason to look for a groove.

That would be totally groovey, man!! :drag:

 

[Geezer]

I think this is caused by you guys cleaning your bikes too much.

 

[gearman]

I'll bet dollars to donuts the groove is due to wear. I've machined countless replacement shafts from samples and drawings over the decades and I've never seen a seal surface that was grooved on purpose.

 

[Canadian FJR]

The only reason that I removed the rear pumpkin is beacuse I started to experience random leaks. The first was after an endurance rally, lots of steady miles at slighgtly higher average speed. I checked the gear oil level and all was well so I cleaned the rim up and life was good. A couple of times after there were some slight splatters but never anything serious. It seemed to only leak after a longer or harder than normal ride. Makes sense.

I am waiting for a respnse from the Yamaha Canada Tech but I am 99% sure that the groove is not suppose to be there. The replacement price is $159.99 Cdn and it is on back order. I can get one from the States for $99.99 plus shipping. Fortunately this is down time for the FJR so I'm in no rush but I am still a little baffled as to how/why this has not been discovered by other folks with more miles. I only have 147,000 km on the bike and as mentioned, I always use the proper Yamalube juice.

Ross, where did you find one for $85.00?

Canadian FJR

 

[gearman]

By positioning the seal on a smooth section of the part the leak is repaired.

I think this might work. According to the pic of the brg retainer/seal near the bottom of this page, the seal could be shimmed out to avoid the worn area.

 

[Canadian FJR]

Nice find.

Canadian FJR

 

[gearman]

If this works we're gonna need to get a seal driver/shim kit circulating.

 

[03HiYoSilver]

If this works we're gonna need to get a seal driver/shim kit circulating.

Wow...what an article. Bad part is I just took mine apart for the spline lubbing and put back together again (took about 1.5 hours) a day before CanadianFjr posted this.

Now you got me tempted to take apart again to Really look at it...even though there are no problems.

Great Post.

 

[RossKean]

...Ross, where did you find one for $85.00?

Canadian FJR

How about here for $73.20!

https://www.georgiawa...idcategory=3452

Its on a Yamaha boat site but I'm willing to bet its the same part. As I mentioned, I just Googled the part number you listed in your original post without key words like motorcycle or FJR. (4H7-46123-01-00). I doubt that Yamaha uses the same part number for different parts - even in a different application. This was, by no means, an exhaustive search!

Ross

 

[Geezer]

Interesting. It appears that there has been an upgrade or modification to the part.

Manufactured by Yamaha

Part #: 4H7-46123-01-00

Replaces , 4H7-46123-01-00, 4H7-46123-00-00

 

[lnewlf]

re post #17 about the harmonic balancer sleeve-I have used these often and they are a cheap and quick repair...getting the right size would be the problem.. Also on some old dozers that I have worked on I have taken grooved shafts to a machine shop where the groove was built up with weld and then turned down to size for less than fifty bucks.

I don't know if the Yammie seal has a spring inside but if so, when the seal wears down to the spring it will cut a groove in the surface..

 

[Canadian FJR]

Yes there is a spring inside the seal but there is no spot where I could see the rubber seal being worn through. My plan is to replace this gear coupling with a new one. I want to have a chat with the Yamaha Tech.

Canadian FJR

 

[Constant Mesh]

Are you sure the leak is occurring at the coupling? One might have an oil leak at the driveshaft seal. As long as that groove was smooth and level with the rest of the coupling don't know why it would necessarily be any more prone to leaking? The groove's width is a small percentage of the overall width so not all that much of the seal area might be compromised. You could plug the drain hole in the swingarm and periodically open it at maintenace time. Probably very little oil is leaving the drive and it likely could be contained for several weeks in the swingarm with the drain plugged.

 

[FJRMGM]

So, to get this straight, you guys that found the groove first had a symptom of a weeping seal, right?

If one of you could confirm that the new part has no groove there, it would be good so the rest of us will know that if the seal isn't weeping there is no real reason to look for a groove.

That would be totally groovey, man!! :drag:

yes - had symptom of weeping seal and replaced the seal. All seemed Ok until when on a long ride and final drive oil got really warmed up then there was a slight weeping of oil and splooge on the rear wheel. Not a bad leak, just evidence that oil was leaking from somewhere on the left side of the bike.

Clean it off and ride a shorter distance and no problem. Ride the bike longer and heat it up and guess what - more splooge on the wheel. So, the seal was almost sealing it up even with the groove. But not quite.

I inspected the new part before it was installed - NO groove in the new part. Smooth as a babies butt.

I have now put at least five thousand miles on it and rear wheel is dry as the day I first rode it home.

And I have to agree it looked worn just like the groove one might find on a harmonic balancer.

 

[Colin24]

Okay, quick update. I'm in the same boat as CanadianFJR on this one. Rear leaky diff. Pulled the unit apart and thanks to a heads up on this one there is a groove in the coupler. I ordered a new one and picked it up the other day ($80 us). And lo and behold, the new one is shiney smooth with no groove.

Hoping to bolt this all back together sometime in the next week or so.

- Colin

 

[Canadian FJR]

The race is on, I also plan to have mine back together this week. Be sure post if you come accross any issues, I'll do the same.

As a side note, I was very surprised in how many different machines Yamaha has used this coupling in. Everything from various motorcycle drive shafts to various jet boats.

Canadian FJR

 

[Canadian FJR]

Gear coupling and new seals installed. Drive shaft is back on. Ready for the weather to break so I can test things out.

Candian FJR

 

[RadioHowie]

Gear coupling and new seals installed. Drive shaft is back on. Ready for the weather to break so I can test things out.

Candian FJR

Looking forward to your first ride report.....in JUNE!

 

[Colin24]

Okay. I got my gearcase reassembled last week too. However I am still rather nervous about this repair.

Not knowing anything about this when I started I just started blindly following the directions in the service manual. In doing so I actually completely disassembled the gear case. In hindsight I am not sure that this was required to change the coupling oil seal.

But it did mean that I had the big bevel gear (not sure of the name) out on the bench. This piece of metal containes the splines that connect to the rear wheel. Inside is the gear teeth that are driven by the piece that comes through the gear coupling.

After cleaning it and preping for reassembly what did I find but more grooves. There are two oil seals for this piece. A giant one that is visible when the rear wheel is removed (just outside the splines) and a small one that is actually hidden inside the casting just underneath where the axle nut goes.

When I inspected the shaft at the point it meets these seals, there where visible lines worn on the metal. The wear marks at both ends were _very_ visible. On the large diameter seal next to the wheel it was still at the stage that the metal was just highly polished. However, on the outboard side (near the axel nut) it was at the point where a groove was just barely starting to form.

I reassembled the unit anyways, the big seal near the wheel was replaced. The little one was not (too hard to get to). At this point I am just going to wait and see what happens once I start putting some miles on the bike. The bike has about 90k miles on it, but I am guessing by looking at the amount of wear on the those other two seals that in about another 50-100 K miles the rear diff will start leaking out of the seal by the axel nut.

Wait and see I guess.

- Colin