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Thread: '78 R100/7 Clutch Spline lube

  1. #1
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    '78 R100/7 Clutch Spline lube

    I am thinking of a project for this winter among several, but the one I wanted to ask about is the Clutch Spline lube on my '78 R100/7.

    I am thinking also at the same time, while I am in there, to remove the clutch (and inspect) and replace the rear main seal. I have no leaking, but I thought I would check.

    Has anyone heard about the concept of supporting the front end of the crankshaft by placing a board (2 x 4) on the front of the crankshaft and pulling it back slightly (like with bungee cords) towards the back of the bike? I have heard of it, and someone recommended it, but I am not sure if reliable source, nor do I know exactly how or why it is to be done. I can surmise though.

    Also, any advice anyone might have I would appreciate.

    Thanks ahead of time.

    jlc

  2. #2
    Registered User godfather's Avatar
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    I personally would not trust bungees. Perhaps tie wire and the 2 X 4 or just stuff some rags under the front cover to fill the void to prevent the crank from moving forward. How about the $4 nylon bolt from Northwoods that is specifically made for this job. (see this page http://www.northwoodsairheads.com/Tools.html )

    If your rear main is not leaking...I'd leave it alone... but thats just me.
    Attitude is everything!
    1978 R100/7
    08' V-Strom 650 great light weight tourer

  3. #3
    Administrator 20774's Avatar
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    Tom Cutter has suggested that many times on the Airheads mailing list. Snowbum shows something that sticks in the front of the rotor bolt and you put the front cover back on. One or more tool places sell a plastic part that does the same thing.

    It has to be done because the crank can fall off of the locating (or thrust) pins or vice-versa. I've never been that far before, but I ran across this photo which should illustrate the pins at the 10 and 4 o'clock positions...the round pins. If these pins get out of place and you later retighten the flywheel bolts, you'll bend important parts and the only way to correct it is to go inside the engine...a complete overhaul.Crankpins.jpg

    Also, Brook blogged about it here...search the page for "thrust":

    http://brook.reams.me/bmw-motorcyle-...-cover-o-ring/

    I also would say, don't go there unless there's an issue. If you go that far, you'll need to do the oil pump cover o-ring as well..."you're there, might as well."
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  4. #4
    Registered User toooldtocare's Avatar
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    I've used rags under the front cover with no problems. I have also had the rear seal go bad on my Motorsport about 6 months after I did the spline lube ruining my clutch. On a bike as old as this I would replace the seal and oil pump O ring just to be safe.

    Wayne

  5. #5
    B Reams brook.reams's Avatar
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    Quote Originally Posted by 20774 View Post
    Tom Cutter has suggested that many times on the Airheads mailing list. Snowbum shows something that sticks in the front of the rotor bolt and you put the front cover back on. One or more tool places sell a plastic part that does the same thing.

    It has to be done because the crank can fall off of the locating (or thrust) pins or vice-versa. I've never been that far before, but I ran across this photo which should illustrate the pins at the 10 and 4 o'clock positions...the round pins. If these pins get out of place and you later retighten the flywheel bolts, you'll bend important parts and the only way to correct it is to go inside the engine...a complete overhaul.

    Also, Brook blogged about it here...search the page for "thrust":

    I also would say, don't go there unless there's an issue. If you go that far, you'll need to do the oil pump cover o-ring as well..."you're there, might as well."
    You will find good pictures of the rear main seal (new version is much better than original) and how the rear thrust washer (large disk with X) fits on the locating pins in my write up which Kurt provides a link to. I also cover updating the oil pump cover to the new version that uses bolts instead of phillips head screws. The oil pump cover gasket leaks in time and the original rear main seal also leaks in time. When you pull the clutch, you will be able to tell if this has happened by the build up of crud under the rear main seal and the oil pump cover. I believe you can see that in pictures in my write-up.

    Note, the problem you can have is the front thrust washer falling off the pins and jamming, not the pins themselves coming loose. I jammed my rear thrust washer and learned a couple things that you can read about in the write-up.

    If you DON'T block the front of the crankshaft as I show in the write-up, then the front thrust washer inside the engine can fall off as well. It's the same size washer as the rear one. When that jams, you have a complete engine tear down and possible major damage to the crank shaft. That said, fire can burn your house down, but we cook with it on our stoves. Proper procedures make the difference between a tasty meal and a charred ruin ;-)

    I also have a write-up on removing and installing a new clutch.
    21 BMW R75/5 Remove and Inspect Clutch

    21 BMW R75/5 Install New Clutch

    Best.
    Brook Reams.
    ---------------------------------
    Brook Reams - Arvada, CO
    Various Two-wheeled Vices, All BMW
    2004 R1150-RS || 2002 F650-GS || 1975 R75/6 || 1973 R75/5

  6. #6
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    I can't tell you all how much this is appreciated! I try to do a lot of watching, reading, thinking and asking before I do stuff. My family always makes fun of me, because when I get something new, I usually don't even open up the package until I have read the manual first.

    I won't do this project until the winter break is here for sure. We still have a few days before then that I can get some riding in - that's why I am waiting - I want to get in every last bit of riding I can before dis-abling the bike for any period of time.

    I think I may go ride today. Supposed to be over 50 deg. and no rain.

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