Who Ya Gonna Call? Grease-Busters!

[3Phase]

My new rear tire arrived earlier than expected so I had it mounted and balanced today. Yay! Matched Metzlers!

While I had the rear wheel off of course I checked the drive splines and coupler grease even though I'd just cleaned and greased them, mmm... (checks odometer) a little less than three thousand miles ago. I had painted the splines with Honda 60 moly grease, then hand-packed everything with high temp moly wheel bearing grease and gave it a couple of good shots with a grease gun after final assembly.


There was almost no grease in the coupler, on the drive shaft splines or in the lower swing arm tube around the drive shaft. Does the grease crawl out of the coupling and sashay up the swing arm tube?

I didn't take the drive shaft out this time but unless half a can of high temp moly grease completely vaporized I suspect it's piled up on the back side of that plate at the bottom end of the swing arm tube behind the lower drive shaft splines.


Is it supposed to do that?


I thought, apparently incorrectly, that the plate inside of the lower end of the swing arm would keep the grease in the bottom end of the swing arm tube. Should I find or make a seal to fit inside the swing arm tube and over the drive shaft to keep the grease where it's needed instead of gradually filling the upper part of the swing arm tube?

Should I stop worrying about it and just keep adding more grease until it starts to come out the top of the swing arm tube and begins to fill the rubber boot at the u-joint?


Regards,

Scott

[TopCatGr58]

Hey Scott,

See this old tech tip regarding the splines/shaft and greasing!

Regrettably due to the outer spline shell, the zerk fitting doesn't direct the grease where it needs to be! Don't know how hard it would be to either tap a hole at an angle to direct the grease towards the splines, or perhaps put a small tube on the inside edge of the existing zerk fitting aimed towards the splines so that greasing WOULD be effective!?

Most folks do this service during their tire changes every 3-6K miles!
T.C.

[3Phase]

Thank you, T.C.!

I read that tech tip while I was refurbishing the bike before going to this summer's Yosemite rally. It's a lifesaving tip that quite literally saved my rear end!

On my bike, one of the P.O.s had managed to 'oval' the lower drive shaft splines inside the coupler and created two high and two low points on the splines. That caused unequal contact points between the coupler and drive shaft that ranged back and forth from excessive to insufficient contact.

Excessive wear occurred on the drive and coast sides at the high points




Minimal wear occurred on the low points (I only took a coast side photo but the drive side is similar)


I replaced the drive shaft and the rubber u-joint boot. The boot had a small tear in it and water had gotten through it and traveled down the swing arm tube. When I separated the final drive from the swing arm tube an unsavory water and grease meringue oozed out and glopped onto the floor.


The tech tip shows quite a bit of grease around and behind the drive shaft splines inside the swing arm tube. Behind that grease is the plate that retained most of the grease (and water, notice the emulsified grease and rust)


The tech tip photo was what my expectations were based upon, so I packed half a tub of high temp moly bearing grease, the black stuff, into: the splines, the concave surface of lower drive shaft end , the tension/positioning spring, the coupler, behind the lower drive shaft end all the way from the inner plate to the gasket face.

After lacing up the final drive and the swing arm, I used a grease gun to add some more grease through the factory fitting to ensure the entire cavity was filled with grease.

When I checked it yesterday all of my grease was gone after only 2700 miles. I had no grease. None. Zed. Zilch. Zip. Nada. Zeeero. No grease.

The grease appears to have been either pumped and slung out of the coupler and spline cavity, up the drive shaft and swing arm tube and then past the inner plate by the moving swing arm tube and the spinning drive shaft, or a chubby green ghost with a giant stogie slimed his way in there and had a snack.

This has drastically changed both my naive expectations and my maintenance interval for greasing the final drive coupler and drive shaft splines.

On the one hand, I really don't want to take the rear wheel off every 2500 miles to hand-pack grease into the drive shaft splines, the final drive coupler, and swing arm tube cavity.

On the other hand, I don't want to ignore it and run the splines and coupler dry or just keep adding grease until the swing arm fills up. Eventually, I will have to clean out the swing arm tube again.

On the gripping hand, a seal or packing of some type in the swing arm tube behind the drive shaft splines would prevent the grease from being evacuated from the cavity but it's going to be a headache to find or build a proper one without creating more problems than it would solve.


Regards,

Scott

[rman]

On the gripping hand,

Love the reference to the book by Niven and Pournelle. A great book and two great authors.