Red Smoke Revival: Bringing an Airhead Heirloom Back to Life

Discussion in 'Airheads' started by Mikepotter86, Mar 2, 2013.

  1. Plaka

    Plaka Brevis illi vita est

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    That's why you do the PM on the nuts. The bike is low on miles but long on years. The nuts have likely never been off. So next tech day you clean and lube them (if you have to borrow a wrench). When the day comes you have to take them off, you want them in good shape. If you are doing a fix 'n' flip on the bike then you ignore them.

    You will be taking the mufflers off fairly soon so you will have a chance to de-carbon the joints and lube those.

    Oil has stuff in it to swell the seals so the fresh oil may be swelling the pushrod tube seals some. Tightening them with the drift is a standard routine you do every so often. Takes 5 sec. per seal and isn't touchy to do. Somebody in the local club likely has a drift.
    #21
  2. Plaka

    Plaka Brevis illi vita est

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    Do you deploy the stand first and then rock it side to side to get it on the 2x4's?
    #22
  3. Plaka

    Plaka Brevis illi vita est

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    Different climate here. That's why we immigrated :-) No need to assume they are seized.

    The cast head is porous. Some of the oils in the antiseize soak in and leave the stuff a bit dry. Worth refreshing regularly.

    The ride-off stand works well. Not your ordinary centerstand. You just sit on the bike and ride away. With a heavy touring load my side stand gets aweful flexy, I don't use it a lot.
    #23
  4. TNL

    TNL Adventurer

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    Great post, Mike! Nice photos too!

    "recently-converted BMW enthusiast friend/neighbor/coworker" :freaky
    #24
  5. kiwi_outdoors

    kiwi_outdoors Been here awhile

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    only if BMW has weird oil.

    as far as I know the only oil that is formulated to swell seals is "high-mileage" oil for older cars and "snake-oil" after-market additives

    deliberately swelling seals essentially accelerates their destruction - its a stop gap measure
    #25
  6. Plaka

    Plaka Brevis illi vita est

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    Snake oil's good...unless you were the snake.

    pushrod tube seals are static seals. Swelling is good. On a dynamic seal I agree with you, too much swelling and the seal will be too tight, won't weep enough, will run itself dry and wear more rapidly. I have to check my sources but I believe all oils have some seal swell stuff and the high mileage oil has a lot.
    #26
  7. Lornce

    Lornce Lost In Place

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    Congratulations, Mike. You've got a fine machine, there. Unmolested R100RT's are becoming rarer every season. Make your father proud. :thumb

    Plaka, Good to see you posting again. :thumb (He's one to listen to, Mike) :norton
    #27
  8. fishkens

    fishkens Long timer

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    OP: Nice bike and a good story. Enjoy!

    100RT: Hope you enjoyed your b-day!
    #28
  9. d mc gee

    d mc gee Been here awhile

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    As Paul(R100RT) mentioned there was a change in the early 80's bikes to brazed push rod tubes. Using a drift can damage the tubes. Also when the time comes to replace the pushrod tube seals there is the issue of getting the tubes back into the head at the proper depth. The correct course of action would be to replace the seals, and at that time also address the exhaust nuts since their removal is part of the process. Needlessly obsessing about the nuts is unwarranted. There is plenty of info on Snowbums website about the very subject. http://bmwmotorcycletech.info/

    You seem to be on the right track, get it running, figure out what the bugs are, get them sorted out, and then ride and enjoy your heirloom. Some folks here would have you tear the whole thing down to the smallest assembly and fix or address any issues that have ever went wrong with one of these bikes. Tinkering with things that need fixed as they come up should be an enjoyable and rewarding experience, and also keep you from becoming mechanically overwhelmed.
    #29
  10. 100RT

    100RT Long timer

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    I have the center stand down then I start with the right side, I tilt the bike then slide a 2x4 under that side then use the lift handle to lift and slide the left side under. To lower I start with the lift handle side. Been doing it for years.
    #30
  11. photomd

    photomd Been here awhile

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    Subscribed. Beautiful bike with a great story: can't wait to read more. :ear
    #31
  12. Plaka

    Plaka Brevis illi vita est

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    Thanks!!

    I shall try this, I think 1.5" lift will do me. I tried some games with rocking it and building up stacks of plywood but wasn't happy.
    #32
  13. Plaka

    Plaka Brevis illi vita est

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    I don't have any problem with the pushrod tubes on my '83. Tapped them completely out of the jugs with the drift, switched them intake for exhaust and put them back with soft face hammer. The depth is totally noncritical, Set them too shallow initially and then set them correctly with the drift after torquing the heads. The tubes are a slide fit in the jugs, not the heads. Didn't notice if the rings on the tube were brazed or welded. Don't imagine it matters. It's not like you are putting big force on them. if you have to, the seals are too hardened and need replacing.

    When I braze stuff the strongest rod I use is Harris 56% silver. The metal will fail before the joint ever does. I imagine BMW can do as well or stronger. Welding can actually make a weaker joint.

    I agree with you (strongly) on the mechanical overload thing. I mention the matter because it doesn't appear on maintenance schedules but is pretty important given the age of the machine. Worth checking out at next opportunity, takes only a few moments. if one is frozen, no biggie, just walk away. Put a new nut on the shopping list and work it into a parts order somewhere. When an opportunity presents with someone experienced at cutting them off at hand, then deal with it. Nice off-season project. The important bit is getting it on the radar.

    You can pull the heads without touching the exhaust nuts, if that needs to be done. So you can replace the push rod tube seals without touching the nuts. To be kosher, you do replace the 3 sealing o-rings at the base when doing the pushrod tube seals and of course the head gasket. You can do it without totally pulling the jugs but it isn't the best way to go unless you are very broke/pressed for time.

    As has been mentioned, unless there is massive leakage at the seals, it is a trivial matter. You can leave it until the pushrod tubes are getting rusty and then deal with those at the same time. The exhaust nut threads in the head are very not trivial. If there is corrosion going on you really want to preserve those threads. A year or so won't matter much but it is a fix sooner than later kind of thing.
    #33
  14. 100RT

    100RT Long timer

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    I must be still asleep, please tell me how to pull the heads with out touching the exhaust nuts. headers, crossover, fairing lowers??
    #34
  15. Airhead Wrangler

    Airhead Wrangler Long timer

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    I was wondering that myself. :ear
    #35
  16. Plaka

    Plaka Brevis illi vita est

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    You have to pull the crossover and the muffler on the side you are working on. ditto carbs. He has the split fairing lowers so he can pull the lowers over the pipes. Rocker covers next. Ever pull the header to adjust valves? Nope. Now you are looking at all the head bolts/nuts. Remove them and unbolt the header support strap at the front engine bolt/nut. The head with header intact lifts away.

    If you have a frozen exhaust nut and you want to get really surgical with getting it off, putting the head on the bench is one way.
    #36
  17. mneblett

    mneblett Professional Lurker

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    Mike, in addition to the steering head bearing tools, I also have an exhaust nut wrench. I also *completely* agree about cutting the nuts off if they only slightly move before tightening up again. Now's the time to start a daily dose of penetrant (e.g., Kroil) to the nut/thread junctions to let the stuff work its way into the threads.
    #37
  18. Lornce

    Lornce Lost In Place

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    Oh, yeah. The steering head bearings...

    At 24k miles I bet you a donut all you need to do is clean out and replace the dried up original bearing grease then correctly adjust the existing steering head bearings.

    imho, fwiw, ymmv,
    Lornce
    #38
  19. jackd

    jackd Long timer

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    That's all my GS needed.
    #39
  20. supershaft

    supershaft because I can

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    I could see maybe leaving the header on IF I didn't have a crossover. Other than that, it sounds like more trouble than it's worth.

    I think installing pushrods like that is just asking them to leak at the cylinder. They are touchy enough there as they are. That is if you are not like Plaka. He doesn't consider an oil an oil leak until it is leaking enough to wash the parts involved clean. Personally, that's right when I stop calling it a leak and start calling it a gusher.
    #40