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Thread: '81 R80 G/S Timing Chain Replacement

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  1. #1
    Day Dreaming ... happy wanderer's Avatar
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    '81 R80 G/S Timing Chain Replacement

    I'm in the middle of replacing the timing chain on my 81 G/S. Had some fun today with dis-assembly but everything eventually came off OK. Oil and lots of dirt and sand in the alternator but very little wear on the tensioner and the chain seemed actually not too bad so I am surprised at how noisy it was with no obvious culprits. We'll see what happens when I get it back together.

    Any tips on removing the old gasket material and corrosion spots from the engine face? I don't want to start scraping and solvent is not doing the trick.

    Another question is the new gasket for the timing chain cover. Can't recall which side goes where. Printed side on the engine side or other way round? I seem to recall the valve cover gaskets go on a specific way and no gasket glue. This one is the same type of material.

    Any other re-assembly tips welcome. I have the Haynes, Clymer and factory manuals none of which contain the details I am looking for.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

  2. #2
    Registered User krpntr's Avatar
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    timing chain

    Hey neighbor, the timing chain is not necessarily the part that stretches. The gears gradually give up material. Not so much that it is obvious, but when you change the chain you want to switch out the gears as well. I tried it both ways with my '82 R100. Replacing the chain without replacing the gears was an exercise in futility. I could not get rid of a floating timing mark till I changed the gears as well. It was lots of fun, you should try it. Rub the gasket material off with a rounded blade tool of some sort. No sharp edges!!! I had good luck with the side of a pick and lots of patience as I carefully rubbed the gasket material off. Some carb cleaner might help loosen the old gasket. Good luck. I don't recall for sure, but I think there is no difference in the orientation of the gasket. If it fits it fits.
    Rub some ATF on the aluminum for the corrosion, Then you can clean that off with simple green and scotch bright. A little Mothers aluminum polish and time will bring the front cover to as much shine as you have time for.

  3. #3
    Administrator 20774's Avatar
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    Are there also some small donut washers as well?

    I can't seem to find any info on gasket orientation. Snowbum's site is here:

    http://bmwmotorcycletech.info/timingchain.htm
    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
    Day Dreaming ... happy wanderer's Avatar
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    Thanks for the help! Later today I hit it with the arsenal. Alcohol, carb cleaner, lacquer thinner, injector cleaner.. the works. The carb cleaner seemed to soften the sticky bits up a bit to the point where my fingernail got some off.

    Something strange about this job is that the mileage is way too low or at least the rebuilt speedo says it is. You know how that goes. PO claims Palo Alto fixed the odometer reset button and some gears and set it back to original mileage which is only 47K kms. The gears look to be as new. Crank gear still nice and sharp cut teeth and cam gear has no visible wear. The guide block is barely marked and the tensioner is serviceable but worn down slightly.

    I can't figure where the noise was. Anyway, the Motobins kit is going in since I'm in there. The new spring for the tensioner is a bit stiffer and longer and the replacement tensioner is thicker so if chain slap was the issue this will fix it. I hope so!

    Anyone know the torque settings for the nut and bolt that hold the guide block down?
    Ditto for the cover screws. Snobum says 68 inch pounds. Don't have an inch pound wrench so have to wing it.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

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    Day Dreaming ... happy wanderer's Avatar
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    I picked up some Permatex gasket remover and a scraper tool that is just a long handled razor blade holder. Hmmm... I will try the ATF and scrub pad on the other stuff today also. Thx.

    Kurt there are some donut washers in the kit and they go on the inside of the cover just above the gasket so that the whole cover sits flat on the engine. Snobum says "measure!" and I think that is because the supplied donut washers are thinner than the main cover gasket so not sure what to do there. I would think they should be the same thickness.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

  6. #6
    Day Dreaming ... happy wanderer's Avatar
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    3 of 5 posts are mine here I guess I am just giving myself a well needed talking to!

    - Just for interest's sake, it turns out the airhead timing cover gasket will only fit on one way so that answers one question.

    - I got a hold of Beemerguru in Philly and he tells me 7 to 10 ft lbs for the chain guide nut and bolt set.

    - I've decided to never EVER use Permatex gasket remover on an in situ object again. That stuff might melt gasket glue pretty good but what it is best at is removing paint. More than a little miffed to find out that _anything_ not totally masked off with two layers of whatever will have paint peeled right off of it by any over spray or splotches. And it comes out kind of foamy so impossible to not get splotches.

    Oh, and it sucks at removing those glued on ancient pieces of paper gasket that are so hard to get off. Which is what I bought it for... I used safety razor blades in a special holding tool I found at NAPA and then some 800 grit paper to smooth everything over. Stains and glazed bits just do not want to come off period. Hoping it is flat enough to seal well.

    Everything clean and ready now, final re-assembly tomorrow. And besides, the hockey game is on in five!
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

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