Sunday, January 20, 2013

Spline Lube

Today's project was lubing the transmission input shaft on my '83 BMW airhead. This is one of those routine maintenance tasks that need to be done every couple of years. The transmission needs to be pulled back about 1½" from the engine to reach the input shaft. This required removing the battery, the battery holder, air filter housing, rear swing arm pivots and the clutch cable. Since the carbs are still off, it made it that much easier. This is the view of the input shaft. The engine housing and clutch is on the right and the transmission housing is on the left. Once the swingarm pivots are removed, it is a simple task to pull the rear wheel, swing arm and transmission back as a single assembly.

This is a dab of Honda Moly 60 mixed with a bit of lithium grease. The Honda Moly is a bit too fluid and would be thrown off of the shaft as soon as the revs pick up. The heavy lithium grease it to help it stick to the input shaft. A regular disposable flux brush is used with the addition of a chopstick stuck into the handle to give you a little more reach. A little dab is smeared on the splines, then the rear wheel is bumped to turn the input shaft a litte and the process is repeated until the shaft has a thin layer of grease brushed on.

Then it is simply a matter of pushing the transmission back onto the engine, insert the cleaned and greased swingarm pivots, air cleaner housing, engine-transmission bolts, crankcase vent hose. Center the swingarm using the pivots, torque the swingarm lock nuts and snap on the plastic dust covers. Replace the clutch pivot and adjust the clutch cable. Replace the carbs, battery holder and battery. Tomorrow I'll adjust the enrichener (choke) cables and throttle cables and pull the rear wheel. The trials tire is in and I think I'll try and replace it myself using the tire irons in the stock tool kit.

12 comments:

  1. This s the second time today I've heard the word spline. My friend's bike s dead n the water because she lost the sprocket bolt. Sounds like a lot of work to me.

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    1. This isn't bad at all. The first time it took most of the day. This time, maybe a couple of hours counting the 30 min looking for the tube of Honda Moly 60. (I hadn't used it since the last time)

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  2. I've got a tube of the Honda Moly 60. Good stuff! I use it every time I take a bike apart, for things like the FJR shaft drive parts and the axles on the bikes. A tube of Anti-seize is a good thing to have too.

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    1. While returning to AK last summer, it would sometimes be difficult to shift and occasionally feeling the bike want to pull forward when first started (in gear but clutch disengaged). Both signs of a dry input shaft splines.

      Honda Moly 60 is great stuff and if you don't loose it, one tube should last a lifetime.

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  3. Richard:

    That's what I need done; a spline lube and also a drive line flush.

    Here's the procedure for the "R1200" hexheads

    http://www.jimvonbaden.com/R1200_Final_Drive.html

    bob
    Riding the Wet Coast

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    1. The spline lube was actually "due" last spring but I procrastinated and then it was time to leave. In the first photo you can see that the splines are dry but not worn out. Given how straight forward the procedure is, I shouldn't have waited.

      Yet to be done is replacing the oil in the transmission, shaft housing and final drive. Replacing the fork seals is a little more involved and I hadn't done it before.

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    2. Richard, this is better than the Hayne's manual. You didn't have to write a Post just for me :)

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    3. Coop:
      The manual makes it seem like much more daunting of a procedure than it actualy is. Very straightforward as are most tasks on these older bikes.

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  4. My favorite part was the chopstick.
    ~Keith

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    1. There's more than one use for those things and we seem to have them laying around all over the place....

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  5. /\ Keith made a funny. :)

    How often do you have to lube the spline? I know you are getting better, and faster, at performing it, but it does seem daunting to me. I'm glad you are comfortable with it.

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    1. According to the guru types on the forums, every year. Realistically, every other year. In the first photo, the splines are pretty dry and it's been 2 1/2 years. After the first time, it really is pretty straight forward. Especially if you don't plan on checking the clutch disc for wear you don't need to remove the transmission.

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