'77 R100s timing chain help

Discussion in 'Old's Cool' started by airheadDavey, Sep 5, 2011.

  1. airheadDavey

    airheadDavey Adventurer

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    I purchased a double row masterlnk chain and was successful with the installation but now have what seems to be a huge issue and I am not sure what to do.

    In order to gian an extra 3/16 of an inch to get the center link on, my mechanic and I loosened the bolts on the flywheel and pulled the crank forward slightly, now with the timing chian on we cannot move the crank back into place and the flywheel will not fuish to the back of the crank. We took the flywheel off and made sure the thrust washer did not fall off the pins. He siad something about maybe there is an oil ridge that it is getting hung on in the journal bearing . With the full tension of the chain on the bearing it wll not go back over the ridge now... We are at a loss to try and figure this out at the moment. I am really hoping that I did not destroy something here.

    Has this happened to anyone? How screwed am I? Is there a way to fix this?
    #1
  2. DeutschMark

    DeutschMark Full Tilt Boogie

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    This is why the crank needs to be blocked from the front when the flywheel is removed. I regret to say that the only remedy is to tear the motor down to put the crank back where it should be. Do not rotate the crank in this condition.
    #2
  3. RecycledRS

    RecycledRS Along for the ride

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    + 1 Sure sounds like the crank thrust washer has come off its pegs. Not good news if this is the case.
    #3
  4. Wirespokes

    Wirespokes Beemerholics Anonymous

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    Are you saying the sprockets didn't line up? :huh

    Try removing the chain and see if everything frees up. How did you determine the inside shim hadn't fallen loose?

    Another scary thing is the flywheel bolts - they have been known to shear off, but don't know if I've ever heard that about the larger 11mm bolts like yours should have. And yours also shouldn't need replacing, it's only the earlier 10mm bolts that would stretch and possibly shear if re-used.
    #4
  5. airheadDavey

    airheadDavey Adventurer

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    I think at this point I am way over my head. Is there a thrust washer internal as well? The rear one is where it should be and did not fall off.

    I don't think that we could handle this situation if the motor needs to be completely taken apart, nor do I think I can afford this type of labor since I would have to bring it to a specialist. Bringing the bike to someone like that in this type of condition to fix and put back together would probably cost thousands. I may have to just sell this bike in this condition and take a massive loss:cry
    #5
  6. airheadDavey

    airheadDavey Adventurer

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    I may have to try removing the chain then. Due to the struggle of getting the chain on my mechanic is reluctant to pull the chain off. He suggested making some kind of rig to push the crank back. From what you guys are saying this seems to be a bad idea if internals may be falling apart.

    This is all my fault. My mechanic has never done a master link chain. He is use to doing this the normal way by pulling the gears off. I also dont think he would have known this was going o happen since he does not work on these type of engines religiously.

    I am going to talk to a specialist tomorrow and see what the worst case scenario cost would be to get this bike back on the road.
    #6
  7. Wirespokes

    Wirespokes Beemerholics Anonymous

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    There is a thrust washer on both sides of the block, and it's the inner one to be concerned about. That's the one that can fall off when the crank moves forward.

    Since you've already re-tightened the flywheel, loosen the cam chain and see if the crank is free. If it is, you're ok. Don't try to force it if it's jammed.

    There's something odd happening here if the cam chain wouldn't go on normally. So are you saying the sprockets don't line up? They're off-set?

    And don't give up so easily - let's figure this out!
    #7
  8. airheadDavey

    airheadDavey Adventurer

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    I am sorry about sounding so negative but it seems every time I fix one thing, something else happens to it and it will never end.

    It did not look like the sprockets were out of line. I did not tighten the flywheel since I could see that gap where it would not sit flush. I may have royally screwed this up on Saturday since we put a block on the end of the crank and gave it a few whacks, it did move but form what you guys are saying I may be just bending shims. I will have to see tomorrow after work when I am back at the shop.:cry My mechanic may refuse further services since he was suppose to have left(quit) this shop a month ago.
    #8
  9. disston

    disston ShadeTreeExpert

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    Davey, it sounds like both you and your mechanic are inexperienced with Airheads. Unfortunate. There are 2 thrust washers. The one you can see under the flywheel and another on the inside of the block, the second one you can't see. The one on the outside, visible, prevents the crank from going forward. The one on the inside prevents the crank from going rearward. The 2 steel locating pins in the block, see the tips of these in the rear thrust bearing, they go thru both thrust bearings. If this is not a clear enough picture please refer to some parts diagram. I tried to find one but it was not a very good pic.

    It is the thrust bearing on the inside that we are afraid has fallen off. By all means remove the timing chain at this point. It is not easy to put the master link in these but it has to be done with the flywheel on in order to prevent what seems to have happened. No short cuts allowed. You will have to fumble with it like all the rest of us. Last time I did one I was two hours just hooking the master link. Other times I have done it in two minutes. With the timing chain off if the flywheel will go on and the crank will turn, you are OK. I don't think this is what you will get tho.

    It is sometimes possible to put the thrust washer back in place by taking off one of the cylinders, or is it both. And putting the washer in place with a long screwdriver. I've heard of people doing it this way but I do not have the experience myself. Maybe somebody here can enlighten us both. It is not the best because in the mean time all the fussing with it can bend, score or damage the washer. It really needs to be in good condition.

    It should be possible to replace this washer with the motor in the frame. It should be possible to do this job out side if you can keep the bike covered when it rains. This is how I do most of the work on my bike and I'm an older guy. Most people can't do this work unless they have a work table and a motorcycle jack and, you name it. They are 1/2 my age and I do this stuff crawling around on the ground.

    There is a special puller you will need if the crank has to come out. Cycle Works has a very good looking one, it's a new addition to their line up. Not cheap but I think it is the only extra thing you will need at this point.

    Charlie
    #9
  10. airheadDavey

    airheadDavey Adventurer

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    Disston, are you saying that if the crank turns freely then I might be ok? Currently the crank turns freely...
    #10
  11. disston

    disston ShadeTreeExpert

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    That is good news. At what stage of assembly are you? Is the flywheel back on yet?
    #11
  12. disston

    disston ShadeTreeExpert

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    The crank has to turn with the flywheel torqued. My bike is older. Your bike has an O-ring and a spacer something, I'm not familiar with this but with everything assembled and the flywheel torqued if it spins easy, smooth, then it's OK.

    Is the timing chain back on yet? Or off?
    #12
  13. airheadDavey

    airheadDavey Adventurer

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    I have not worked on it today. I am going off of the way we left it saturday. The chain was on and the flywheel snugged but there was the gap showing the crank was moved forward still. The crank was able to turn so i am going to take the chain off tomorrow and see if i slides back into place. Reading on Airheads forum I can put the link through the front which seems it will make things easier. Thank you for all the help, I will let you know what happens tomorrow.
    #13
  14. disston

    disston ShadeTreeExpert

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    So if you can see a gap? You are looking inside the block, through one of the holes where the cylinders go? You have the jugs off? This id fortuitous if it is the case. You can see what is happening with one or both of the cylinders off. If they are not off then you will want to remove them if taking the timing chain off doesn't improve things.
    #14
  15. Airhead Wrangler

    Airhead Wrangler Long timer

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    Pull the right jug; It's the easier to see through the right jug-hole.

    There's a thread around here with a great photo of the thrust washer in question in its dislodged state. Search around here for "block the crank" or something like that and you'll find it. Sounds like a case of needing to RTFM. Sorry man.
    #15
  16. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    #16
  17. Wirespokes

    Wirespokes Beemerholics Anonymous

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    If the flywheel is snugged down and the crank turns, then you've dodged the bullet.

    If the shim came loose, then jammed (getting bent in the process - they bend easily) and then magically somehow got back on the pins - there's no way the crank would spin!

    So if the flywheel is snugged and the crank turns - then breathe a sigh of relief.
    #17
  18. fishkens

    fishkens Long timer

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    This may be the best thing that ever happened to your airhead. :(

    Changing a master-link timing chain is a bit persnickety but it isn't a struggle. Depending on how hard you whacked the front of the crank you may have damaged the internal thrust washer.

    Best case is that you pull the right jug and see a) that the thrust washer hasn't dropped off the locating pins or b) it isn't damaged (difficult to see) but can be repositioned onto the pegs. Then you can tighten the flywheel bolts and confirm that the crank turns before putting the jug back on.

    Good luck! (and get some manuals - I don't recall any manual suggesting that the flywheel bolts be removed to install a timing chain).
    #18
  19. airheadDavey

    airheadDavey Adventurer

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    Thanks for all the suggestions guys. I just got a quote of $600 from a very reputable BMW shop bringing the bike in at its current state and get everything done properly. This would be (best case) if all that is required is to take the timing chain back off, right jug off, and slip an undamaged thrust washer back in place and completely put together with flywheel on and timing set. It may be less if the washer is not dislodged.

    I do plan on kepping this bike for a long time and know most say I should do this myself, but in this case I need to leave it to the pros. I dont have a place to do this extensive a job since I live in an apartment. If I had a garage and did not have to worry about being in someones way I would try.

    I will be doing the clutch, trans, driveshaft ect.. myself since I can do that with my eyes closed.
    #19
  20. airheadDavey

    airheadDavey Adventurer

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    Ok guys I got the chance to look at the bike today. I took both spark plugs out and was able to turn the crank easily with the timing chain on. I did take the timing chain off and tried to push the crank back and it seemed to not move. I put the flywheel on and it is still not sitting flush. I am not sure where the problem could still be??:huh

    I guess this means the internal thrust washer has not fallen off so it should be less than the original quote of $600. But this will be my first time going to this new place so I hope they will be honest with me. It takes me a long time to gain trust in people with my vehicles.
    #20