First Real Work on GSPD - Drive Shaft Removal

I picked this GSPD up almost a year ago non-running and after a couple clean carbs and new cables that fit the Mikuni cards she was up & running. Things like wife, kid, house, football season, homebrewing etc got in the way of any more work or riding until now and I finally got around to changing the busted drive shaft boot.

When I loosened up the rear boot oil starting coming out so I guess the final drive is leaking and when I finally got the swingarm off it was pretty dirty inside. I cleaned off the drive shaft and I think it's OK and the u-joints aren't loose or anything but I"m not sure of the best way to clean the swingarm. Anything else that I should check?

Bottomless German


Nasty Rear End


Swingarm Off


Inside is Dirty




Bearings




Drive Shaft

Have you been keeping track of your transmission oil levels? It could be leaking out the rear seal. If you have been keeping track of the rear drive oil or measuring how much you put in vs how much comes out, you would have another indicator of the source. Either way, check both levels. If it's old or contaminated, change it. The good news is if it's a rear tranny seal, it's easier to change than the 4 speed. The bad news, if it's coming from the rear drive... If I am not mistaken, you want to avoid getting oil or solvent in the shock absorber part of the driveshaft. You may be a bit past that, but fortunately everything drains down...

I've only ridden it around the block once and haven't changed the engine or transmission oil yet.

Is the rear drive seal hard to change?

It's too late now, but anytime I get a new bike running, I ride it until the oils are warm and then drain, measure and inspect what comes out and fill to spec to establish a baseline. Do that now. Inspect the trans oil for water and the drain plug for gritty chunks. Measure what comes out to see where leak was coming from. Drain the rear drive and measure what comes out too. It's all forensic science at this point.

Already drained the final drive when I saw the oil all over the place. :/

It did look like the area where the drive shaft attaches to the engine was pretty dry relative to the lower part but that could be gravity's part.

For cleaning that kind of gunk, I just use wd40 from a jug, you can get it at the box box home centers. Mineral spirits work just as well but I hate they way it smells.

Simple green or pinesol should also work.

I use rags and brushes, having found that both grout and stripping brushes work really well for cleaning this kind of stuff.

There's a mild acid products that will brighten up cast aluminum pretty well, just if you use it err on the side of rinsing it off in shorter durations rather then letting it sit for longer.

Dont get the solvent near bearing surfaces or races.

My GS had gear oil in the paralever too. Most likely coming from the transmission output seal. Probably not a big deal...just a notch to be plugged with sealant. Check this link http://www.advrider.com/forums/showthread.php?t=757207 I believe that there is also a service bulletin floating around on this and more threads on the subject if you search.

It does look like the gearbox is leaking cause I see some oil up there but where is this notch that I need to plug?

That little teeny tiny V notcvh at 12oclock, in there

The transmission and final drive may not be leaking at all. It's possible the PO poured gear lube in the swingarm to help the u-joints - not an uncommon solution.

Clean the rear drive....stand it up on its end. You'll find out soon if it leaks. Less than 24 hrs depending on the leak.

Good idea, I'll do that tonight. Now what kind of oil? Kidding, I don't want to start that argument, I'm going with Royal Purple 75w90.

What grease is good for the drive shaft splines?

A good moly. Honda Moly 60 is popular.

This is a photo of the transmission output seal from my 1989 R100GS. The V-shaped notch is at the 12 o'clock position. The notch is not plugged.

It should be plugged. I have the very same transmission here, recently rebuilt by a well known specialist and it is plugged.

Yes I had that leak back then, the technician should have read the bulletin.....a little sealant is a lot cheaper than a new "leaking again" seal area. Seal wasn't the problem....!!!

Last time I ever went to a BMW shop for any work....back in 93??? 94????

Clickety click....bulletin appears. Now you can make all you want of the procedure to re-apply sealant.:eek1 I know the orange stuff I applied myself after lasted 15 or so years. Must have been good shit....my old boots of the same vintage have some on them and still well stuck there.

Picked up the Honda Moly 60 and it reminded me that I have some other brand moly lube from when I put a big bore in my KLR but its a liquid and this Honda stuff is paste.


Can the notch be sealed as is or so I have to take the gearbox apart?

Dont have to take the whole box apart.. but it is a little fiddly to get the RTV all daubed up in there.

Also the new de facto trans vent is through the where the speedo cable comes out. specifically, through a hole in the bolt that holds the speedo gears in, and often the battery ground.

Most commonly stripped bolt on the bike, second only to the center valve cover stud.


ANyway, be gentle on that bolt, but make sure its clear, otherwise venting problems. While youre at it, use some of that sealer around under the boot of the speedo cable. Water runs down and infiltrates the gearbox through there.


Haha, you came here to drain the swamp, didnt ya :lol

Do I need to replace a bolt with one that is vented?

unless someone replaced the stock bolt with a hole-less bolt, it should have a hole innit.

If it doesnt, it would explain why the gearbox was puking oil into the swingarm.

BTW- wirespookes- I've never heard of people putting a bit of oil in the swingarm to preseve the cardans. I've only ever heard that the oil that inadvertently gets in there tends to pooch the driveshaft rubber, and thusly () the driveshaft itself

hell, even the shafts with oil technically dont need it. (oil)