Oil in swingarm/final drive help!

So I removed my rear tire today and discovered alot of built up oil crud on the inside of the final drive unit on the drive side. There was some light rust inside and out, so i was going to take it off and repaint it. i figured i would remove the whole swimgarm as that could use paint too. When i pulled back the rubber boot thing a bunch of oil spilled out of it. I'm pretty sure this shouldn't happen? I'm assuming a seal is bad just not sure where. Also, anyone know how to loosen those 4 bolts on the drive shaft? Couldnt get them to budge. Thanks in advance for the help.

 

Use a quality box-end wrench and give it a whack with a hammer to shock it loose.

Is it motor oil or rear-end lube?? Motor oil should look more black.
That's the output seal failing.

The "built up oil crud" in the rear could be normal neglect, or the rear seal going. Check your rear brake shoes while you're in there.

 

yeah i checked them. That was really all a planned to do before discovering the rest. Is that seal easy to replace?

 

Someone else will need to answer - I haven't tried that one.

 

The Input flange on the driveshaft is easy. Put the final drive and wheel back on. put a 12mm closed end wrench on the nut and Put another open end wrench on the end of the 12mm for added Leverage. as you put pressure on the nut, put the bike in gear and hold the rear wheel in place to keep it from rotating. once you have it loose, take it out of gear and rotate the tire o get to the next nut. repeat until they are all loose and hand thread them out. I've never done the output shaft seal on a bike but done many on manual and auto trans cars. Usually takes an impact gun to remove the large nut holding the splined output flange. At that point I imagine you can remove the case cover and press out the seal. On 4 wheel transmissions with no case cover to be removed I would usually drill two wood lag screws into the metal part of the seal and yank it out with vice grips. Someone else may chime in with an easier way.

 

Are the oil seals lipped into the engine case? or just pressed in? If so you may want to hold off until the winter before you attempt to replace and enjoy the bike through the summer!

 

Ok thanks everyone. I got the swing arm off and getting ready to get a new seal and o-ring from chacal. Now to just clean off years of oil grime for new paint.

 

Here is some advice for you newbike, don't mess around with the final drive yourself, it requires a Yamaha tech to do it right. As for the oil in the boot, you may need an output shaft seal, but removing the drive shaft flange will require an impact wrench, socket and a way to immobilize the flange.

 

Has anyone ever tried doing it themselves? Taking it somewhere really isn't an option right now. Is there much danger in leaving it for now as long as make sure to check the oil level often?

 

i think Steve is talking about the deferential, the part the axle goes through, that can get complicated. if your talking about the seal on the engine, thats doable but the housing that it's in might be tricky to get back in the "block" because of the big o-ring. i never had to replace the seal but, hay, how hard could that be

 

In order to remove the out put shaft seal,
1)Get a manual
2)loosen the two case bolts that straddle the output shaft flange, just loosen a little bit.
3)remove the four bolts that hold the out put shaft flange.
4)the out put shaft with flange should slide out. sometimes with a little difficulty just don't get it cocked one way or another, and don't loose the shims
5)once out take the nut on the out put shaft off and slide the shaft out.
6)replace the seal like you would any other seal
7)reassemble in reverse order

 

Ok thanks alot thats really helpful.

 

RAZZ! you have it all wrong! you don't take the seal carrier out of the bike, you don't remove the four bolts that go into the case. To change the shaft seal, remove the large nut from the center of the flange. then you can change the seal.

 

I am sorry lvsteve. I have changed three out using this process. I have also tried it your way with MUCH more aggravation due to the tight space, and trying to remove a seal that is tightly installed around an installed shaft. Take the carrier out, take the shaft out of said carrier. Then at the most use a seal puller, and at the least pop it out with a large screw driver. I sir do NOT have it wrong, just an easier way of doing it. The manual gives instructions with the shaft remove, so if I am wrong, as you so flamed me them the gentlemen that wrote the book is wrong also, you want to flame them too.

 

I do have serious concerns about what Haynes has to say in their book, it's badly written and the tech drawings are second rate. Then there are the errors. Except for those problems with the Haynes manual, it's a fine publication. As for your method, do it how ever you wish, but I am of the opinion that your way is incorrect because it's not a requirement that you remove the carrier. I believe you just don't have the right tool for pulling the seal. Sorry I hurt your feelings, but it's not a crime to say that someone is wrong.