Driveshaft Gear Coupling

There has been plenty of discussion on various rear end leaks so once the season was over it was time to pull mine apart. It leaked only slightly and not all the time. I figured that it was one of the two seals discussed in previous threads. Once the gear coupling (Part # 4H7-46123-01-00) was removed from the housing I found a perfect groove all the way around the coupler where the seal makes contact. Can anyone verify if that groove is suppose to be there?









Canadian FJR

don't know, but from the pics it looks like the surface along the bottom of the groove was getting hot?

I wonder what the chances are that some dealer has one of these sitting on a shelf........I would like to see if a new one has that groove.

The only thing in contact with that coupler is the inner seal.

Canadian FJR

I don't suppose the microfiche goes into enough detail on this part?

I can check tomorrow.

Canadian FJR

Something doesn't look right seeing that there is some discoloration going on. My guess is that it has been scoured for some reason. If it was a snap ring groove you would have pulled it out. fortunately you have caught it sooner than later.

Dave

Canadian FJR said:

I wonder what the chances are that some dealer has one of these sitting on a shelf........I would like to see if a new one has that groove.

The only thing in contact with that coupler is the inner seal.

Canadian FJR

Click to expand...

If that is where the seal seats then that grove is not suppost to be there.

Hey - I have a coupling that looks just like that sitting on a shelf in the garage.

NO - that groove is not supposed to be there and is the reason for your sometimes oil leak.

Last spring I had a problem with oil splooge on the rear wheel of my '05 with 76,000 miles and replaced seals once at a dealer and after a while it leaked again, but usually only after I had ridden a good distance and really heated up the final drive oil.

The second dealer I took it took had just replaced that coupling part on another '05 FJR and had a pretty good idea of what the real problem was.

And it was because of that groove in the coupling, which allowed a tiny bit of oil past it when the oil was good and hot.

I believe it was about $120 for the coupling which took two days to get and another new seal and I have been oil-free ever since.

Replace the coupling and the seal.

That is the info I needed. Thanks for the reply.

I am willing to bet that this has been missed during more than one seal replacement. It looks like it was machined that way.

Canadian FJR

ok, so now i'm curious, how does a groove like that get there and how do you stop it from getting on the new coupler?

My 07 has 103k miles, and whilst i've not inspected the coupler, i've not had any oil seepage either so assume it's ok.

I have just slightly less milage that that and always used the proper Yamalube rear end juice. The only thing that touches that gear coupling is the inner seal. Hard to believe but it must have been caused by that rubber seal. I just checked on ordering one and they are on back order.................... <_<

Canadian FJR

Speculation would be that some road grit somehow got up under the lip of that seal and wore the groove?

How does the lip of that seal look? Any foreign stuff melted into it?

Perhaps attempts to clean the seal from the outside would have helped in forcing the grit up under the seal edge?

Odd. 226,000 miles and I never had to replace the coupler. I did have to replace the seal that goes around it on two different occasions. I had a dealer do the work on mine, so I never actually saw what the coupler looked like.

Odd.

"Speculation would be that some road grit somehow got up under the lip of that seal and wore the groove?

How does the lip of that seal look? Any foreign stuff melted into it?

Perhaps attempts to clean the seal from the outside would have helped in forcing the grit up under the seal edge?"

That was my thought also Fred but there is no sign of any foreign material. Theseal looked good. If there was a rock or some other particle I would assume that the cut would be slightly more irregular.....this cut is perfect. As I said before, I likely would have buttoned things back up because it looks like it should be there. No shame on the bike with the number of miles, I'm just a little surpried that it has not been mentioned in earlier posts.

Canadian FJR

Nice catch CanadianFJR. And just in the nick of time!

My rear gearcase is apart and on the workbench as I write this. I ordered all the parts last week, they came in yesterday and I was going to put it back together this weekend. Got your email giving me a heads up. so first thing I do out in the shop is grab the coupler and inspect.

And YUP. There's the grove. And a very close look with a magnifier (to me) tells me the groove is worn in and NOT machined in.

So the gearcase stays apart for another week or two 'till I can get a new coupler.

And Again, thanks for catching this one and the personal heads up! I likely would of buttoned everything up and wouldn't have had a problem. At least untill I had 5 or 10 K on the repair and then it would have likely started oozing again. And that would have occured right in the middle of an 11 day ride I am doing next June. Thanx

- Colin

Try Googling just the part number. I did it to see if I could find a picture on-line of the part. No pictures other than low resolution parts fiches but its amazing what Yamaha has used this part in. Found one source under $85 - for a boat, I think.

Ross

It is a common problem on some harmonic balancers on car engines. There are sleeves sold for the balancer that press on over the grooved area and provide a new surface for the seal to ride. Maybe one of these would fit.

www.summitracing.comSearch Results$14.04

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Colin24 said:

And YUP. There's the grove. And a very close look with a magnifier (to me) tells me the groove is worn in and NOT machined in.

Click to expand...

I don't know. If there are so many with grooves, I am starting to think it is supposed to be there. If this is so common, why aren't there more leaking out there? How many miles do you have?

The groove looks sooo perfect, wondering if this is a batch of parts that got through QC or a possible

cross over part for another model (and the grooved part would affect its applied function).

Hope your new parts solve the mystery.