Page 1 of 2 1 2 LastLast
Results 1 to 15 of 19

Thread: '81 R80 G/S Timing Chain Replacement

  1. #1
    Day Dreaming ... happy wanderer's Avatar
    Join Date
    Mar 2010
    Location
    Vancouver, B.C. Canada
    Posts
    2,030

    '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
    Join Date
    Jan 2010
    Location
    Mt Vernon WA
    Posts
    409

    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
    Join Date
    Sep 2005
    Location
    San Antonio, TX
    Posts
    13,600
    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
    Join Date
    Mar 2010
    Location
    Vancouver, B.C. Canada
    Posts
    2,030
    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

  5. #5
    Day Dreaming ... happy wanderer's Avatar
    Join Date
    Mar 2010
    Location
    Vancouver, B.C. Canada
    Posts
    2,030
    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
    Join Date
    Mar 2010
    Location
    Vancouver, B.C. Canada
    Posts
    2,030
    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

  7. #7
    Registered User
    Join Date
    Jun 2006
    Location
    Lethbridge, AB
    Posts
    50
    Have been following this post as I have a "noise" in my R80 as well. Would you do a follow up as to the success of the repair and perhaps a little more information on the type of noise you were looking to repair. My interest was piqued when you mentioned it was difficult to locate and determine where it was and what might be causing it. thanks
    "Fools that we are, we have gone to war with nature. If we win, we die.". Silver Donald Cameron

  8. #8
    Hacker
    Join Date
    Aug 2009
    Posts
    26
    You should always replace the gear on the crank. The large gear on the cam shaft is rarely changed.

    Yes the main gasket only goes on one way. Make sure you don't forget the small donut gaskets. They come separate. This gasket is not a three part set. You need one main gasket and two donuts.

    I use straight edge razor blades to scrape and cut gaskets off. I may scratch the Aluminum a little but this is inconsequential. The gasket surface does have to be flat and free of defects. Tiny scratches from getting gasket material off are OK.

  9. #9
    Day Dreaming ... happy wanderer's Avatar
    Join Date
    Mar 2010
    Location
    Vancouver, B.C. Canada
    Posts
    2,030
    Job is done and the bike runs fine. I set the timing based on a photo I took before removing the Hall Sensor can and it was astonishingly close. Just a tweek needed to get it bang on. I still have a double image though.

    The bike is much quieter. I did not need to change any sprockets or bearings in there. No heat was required to get the cover off or back on either. That sort of surprised me after reading Snobum's description and 3 manuals on the procedure to get in there. Both sprockets looked brand new and I suspect the biggest change in noise was due to a longer tighter tensioner spring. None of the other parts really needed changing IMO but since I had the kit and was in there I did so anyways.

    The lack of any chain noise now has made me aware that most of the racket is actually coming from the clutch area and it goes away when I pull the clutch in. So I am not sure if that means the throw out bearing is worn, the splines are dry, the input shaft bearing is noisy... but since it goes away with the clutch pulled in and that pushes on the throw out bearing I'll lay my suspicions there for now. I have to do some reading on that. It's riding season though and whateve it is will probably have to wait for winter. I plan to ride it to the National and that was the point of this exercise anyway.

    I have a front wheel bearing grease tool and a swingarm grease gun attachment now that I plan to try out. It has been a while since I adjusted airhead carbs but I should do that also. I'll try out my oilhead synch tool on them and see what happens there.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

  10. #10
    Hacker
    Join Date
    Aug 2009
    Posts
    26
    The noise from the transmission in neutral is probably from the shifting mechanism inside the trans. BMW tried to eliminate this noise by the addition of several O-rings on the shifting cams. It didn't really help. Those parts are still shown on the parts diagrams but most rebuilders leave them off.

    The noise can be effected by the balance of the carbs and the double timing image. Since you did not change the crankshaft gear you are probably stuck with the double image. My bike is older than yours. The rattle in neutral is pretty loud I think. But I have learned to ignore it. It doesn't cause any harm.

    The older bikes like mine that have a points plate and ignition points have a way to eliminate the double image by bending the tip of the cam shaft. Since an '81 bike does not have this tip you can not use this technique. If the dots of the image are only 2 or 3 mm apart it is said it is OK. If they are farther apart then it should be fixed. Makes for a loopy idle. I used to say my Airhead sounded like a Harley.

  11. #11
    Administrator 20774's Avatar
    Join Date
    Sep 2005
    Location
    San Antonio, TX
    Posts
    13,600
    Quote Originally Posted by happy wanderer View Post
    The lack of any chain noise now has made me aware that most of the racket is actually coming from the clutch area and it goes away when I pull the clutch in.
    Depends on what sort of "racket" it is, but generally, they all do this. I'd say you're looking for a problem that doesn't exist. Ride on!
    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!

  12. #12
    Day Dreaming ... happy wanderer's Avatar
    Join Date
    Mar 2010
    Location
    Vancouver, B.C. Canada
    Posts
    2,030
    I have to agree Kurt. She's goin to the rally the way she is.

    As for the double image it is tiny. Like 1mm or 1.5mm tops. I read about it in the manual so I mentioned it but it does not concern me. As for the crankshaft pulley, with beautiful square edged teeth why would I change it? Until the tips are thin and somewhat sharp on the end there should be no real issues.

    Been trying to button things down for the last three days but I have been stricken with a new health curse. GOUT! I woke up three days ago and could not stand on my left foot. Man was my big toe swollen! Got way worse and I threw in the towel and limped to the hospital today.

    They confirmed what my little darlin read in her medical books. She's always right. I hate it when that happens.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

  13. #13
    Hacker
    Join Date
    Aug 2009
    Posts
    26
    Square teeth on the gear do sound right. Not sure where else the double image could be from. Almost touching should not be a problem.

    My double image has recently reappeared. It's about 2 or 3 mm. This not 2 or 3 degrees. It is probably 1 or 2 degrees, I think. I'll leave it alone for the Summer. Too many other things going on. But for the points plate bikes like mine we can cheat and correct it.

    I have an extra flywheel around here somewhere. Maybe I'll measure the circumference and see what a degree of timing is.

  14. #14
    Administrator 20774's Avatar
    Join Date
    Sep 2005
    Location
    San Antonio, TX
    Posts
    13,600
    Cirumference should be 720mm, so the 2mm represents 1 degree. Except probably the R45/R65. Slightly smaller circumference for the /2s.
    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!

  15. #15
    Day Dreaming ... happy wanderer's Avatar
    Join Date
    Mar 2010
    Location
    Vancouver, B.C. Canada
    Posts
    2,030
    Still hurts my toe to shift gears but the gout settled down enough to put a couple hundred kilometers on over the last few days. What a pain in the ... toe? Sheeesh.

    The engine is quieter and seems somewhat smoother as well. Happy to see no leaks after a dozen or more heat cycles. I did some carb adjustments. Mixture by ear, then idle stop screws with the Harmonizer and finally the throttle cables with the Harmonizer. Pulls up from an idle better now but a bit of popping decelerating downhill so maybe too rich. Have to read up some more on fine tuning carbs again.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •