Airhead "Tips and Tricks"

Discussion in 'Airheads' started by elmoreman, Sep 26, 2006.

  1. Ponobill

    Ponobill Adventurer

    Joined:
    Aug 24, 2021
    Oddometer:
    84
    Location:
    Oregon
    Good news, bad news, good news, bad news... Sheesh.
    So I pulled the transmission out in what probably is record time, heated up the cover and popped it off. I re-measured everything and sure enough, the input shaft actual float was somewhere in the neighborhood of nothing. As soon as I slacked the bolts the shafts got easy to turn, which simply meant I fucked up the end float.

    Good news--I shimmed all three shafts to 0.10 mm, closed the transmission back up, and presto--turned like butter.
    So I spun the shafts while I shifted through the gears .

    Bad News--the 3rd to 4th shift was very hard and made a strange grinding noise when I turned it through several rotations. I pulled the cover back off (yes, I had to pull the output flange again, yes, I had to heat the cover to 270 to get it off, yes, I burned myself for the twelfth time despite my gauntletted glove).

    Peering into the guts while I turned the shafts I spotted one of the larger gears touching the end of the spring of the cushion clutch for the input shaft. WT holy F??
    I had previously disassembled the shaft to check out the cushion faces, decided they were good and put it back together. I didn't pay much attention to which way the spring went, perhaps it matters? Anyway, I pulled the output shaft and took it apart, being careful not to mash the sheet metal deflector shield.

    Bad news--In the process, I hooked the edge of the tophat bushing that presses into the lower bearing and cracked off a piece. Several thousand choice words later I finished pressing out the damaged part, screwing up the pushrod seal in the process.

    Good news--no problem, I bought a spare.

    Good news--could probably use the damaged bushing, it would probably be fine, though there is a remote chance it might not be. But then

    Bad news--I discovered that I didn't have a spare seal--I damaged one putting the thing together and used the spare.
    More choice words, but I went upstairs to my computer and ordered the parts I need.

    Good news, I can get the seal

    Bad news, the tophat bushing is on order

    So now I wait, calm down, and get my shit together.

    Good news, I went home, made the world's best bacon cheeseburger, and washed it down with a nice glass of Analemma Grenache. Nothing takes the taste of humiliation out of your mouth better than one of my masterpiece burgers. They really are a work of art.
    +venture, BJMoose, Achtung and 16 others like this.
  2. Disston

    Disston ShadeTreeExpert Supporter

    Joined:
    Aug 31, 2009
    Oddometer:
    19,056
    Location:
    Silver Spring, Md
    SmittyBlackstone and Chad M like this.
  3. Jim K in PA

    Jim K in PA Long timer Supporter

    Joined:
    Mar 15, 2011
    Oddometer:
    5,744
    Location:
    Pocono Mountains, PA
    You are still winning, @Ponobill . Patience and killer CBs will get you to Valhalla. ;)
  4. Ponobill

    Ponobill Adventurer

    Joined:
    Aug 24, 2021
    Oddometer:
    84
    Location:
    Oregon
    I put the transmission together today, just waiting for the clutch rod seal so I can put it back in the bike. I decided to salvage the bushing even though a chunk of the tophat was broken off. It doesn't affect the stability or the position of the bearing. I examined the bushing under a microscope I use for doing surface mount soldering and eliminated any high spots with some careful filing with jeweler's files. My preference would have been to replace it, but given that I can't seem to find one available for delivery anytime soon, it seems that repairing the part was the best option. I pressed everything back together and I'm happy with the result. I redid the shimming and wound up removing one 0.1mm shim from the input shaft stack, I put it all back together. It turns smoothly with a level of drag I'd expect from new bearings and seals. And it shifts fine. I lost a few days, but if the seal shows up when it should I will have this all back together soon.

    Since I cleaned up and was done early I offered to cook dinner and asked my wife what she preferred--the nice rib-eye steaks I bought a few days ago or cheeseburgers again. She chose cheeseburgers. I do love that lady.
  5. Arktasian

    Arktasian Feelin the BMEP

    Joined:
    May 23, 2014
    Oddometer:
    2,270
    Location:
    BC
    Had a chuckle at your "Good News/ Bad News" post up there. Haven't we all been there, but I think you're more persistent than most - I'd have gotten side tracked with the "lost tool that I tried to blame on the wife", then back peddling furiously once found & the situation stopping its downward spiral.
    What's the pressure cooker like device in one of your earlier posts? (I'm thinking not a still).
  6. Ponobill

    Ponobill Adventurer

    Joined:
    Aug 24, 2021
    Oddometer:
    84
    Location:
    Oregon
    It's a resin trap for vacuum-bagging composites. I do a fair amount of composite construction, mostly watersport stuff these days but it used to be motorsports. Vacuum bagging is a technique for forcing the composite layers tightly onto a mold or foam shape using a vacuum pump. Sometimes the resin gets past the various layers used to distribute the vacuum and gets into the vacuum hose. When that happens, having a fifty-buck resin trap pot prevents damaging a thousand bucks worth of vacuum pump.
    Disston likes this.
  7. Ponobill

    Ponobill Adventurer

    Joined:
    Aug 24, 2021
    Oddometer:
    84
    Location:
    Oregon
    I got the BMW back together. I did some very involved stuff with the wiring, adding a new fuse block with fancy-schmancy LED blown fuse indicators. After connecting everything I decided it was too unhandy and ripped it out. Back to simple in-line fuses. I'll try something clever next year.

    I took it for a short ride and everything works well. the transmission shifts perfectly, the new clutch is a bit on the instant-on side but that will clean up on its own. I decided to play with the swingarm bearing alignment to optimize wheel alignment because I felt it might be funky--I noticed some tendency to wander previously. That isn't usually done since the swingarm centering spec is fairly tight (.5mm) but I felt it would be a good indication of frame straightness. I fiddled a bit and got the wheels aligned to less than 1mm misalignment and the swing arm gap was right on with less than .1mm variation. Yay. I set the preload at 10nm since I didn't replace the bearings.

    I haven't tuned it up yet and didn't sync the carbs, so it's a little rough, but overall, a good start to making this bike exactly as I want it.

    Attached Files:

  8. Arktasian

    Arktasian Feelin the BMEP

    Joined:
    May 23, 2014
    Oddometer:
    2,270
    Location:
    BC
    Well, that makes sense. I'm no stranger to vacuum-bagging, although I am not a composite tech as such. A company I worked at manufactures very large amphibious craft in a Marine "Split Hull" type arrangement (Arktos)
  9. walkingbear

    walkingbear Lets Play Chicken! Supporter

    Joined:
    Jun 5, 2004
    Oddometer:
    5,308
    Location:
    Scottsdale AZ..
  10. Achtung

    Achtung Wicked Pisssah Adventurer Supporter

    Joined:
    Nov 1, 2002
    Oddometer:
    3,694
    Location:
    Waltham MA
    So I bought this 84 R100RS project today and the story with it was that the PO tried to do an oil change two years ago and couldn't get the OF cover back on.
    He left the bike sit with the oil filter cover/ oil cooler hoses dangling off and after some time lost interest in riding and eventually it ended up in my garage.
    I put it up on the lift and discovered pretty quickly why he couldn't get the cover on, he'd installed the oil filter backwards and now the half of the filter which should be facing out is facing in and it's stuck pretty good on the inside the filter tube.
    I'm planning to pull the exhaust so I can have decent access to fish the 1/2 of the filter back out but I'm wondering if anyone has run into this before and can give a trick to getting it out.
    Please excuse the "barn fresh" patina.
    Thanks
    [​IMG]
    Uke, globalt38, dazz and 1 other person like this.
  11. melville

    melville Long timer

    Joined:
    Jun 19, 2010
    Oddometer:
    3,626
    Location:
    Just Outside the Redwood Curtain
    I use a bicycle spoke as a hook to pull filters out of the can. But mine aren't jammed wrong way in.
    SmittyBlackstone and Achtung like this.
  12. Disston

    Disston ShadeTreeExpert Supporter

    Joined:
    Aug 31, 2009
    Oddometer:
    19,056
    Location:
    Silver Spring, Md
    I don't get the thing about the filter being installed backwards. There is no backwards. The filter can go in either way, it's the same either way. Maybe you can take a pic for us ?

    EDIT: PS, these bikes have what has become known as the "$2,000" oil filter. It's to do with the O-rings and the cover. It must be assembled correctly or you may destroy the engine. Suggest again take some pics.
    Uke, SmittyBlackstone and korinthias like this.
  13. Achtung

    Achtung Wicked Pisssah Adventurer Supporter

    Joined:
    Nov 1, 2002
    Oddometer:
    3,694
    Location:
    Waltham MA
    It's an oil cooler bike. The o ring portion of the filter goes in first. If you try to put it in backwards it can get stuck on the tube. At least that's what I'm assuming happened. He never started the bike afterwards so it should be fine.
    upload_2021-11-3_10-20-2.jpeg
    Uke, kbasa and SmittyBlackstone like this.
  14. Disston

    Disston ShadeTreeExpert Supporter

    Joined:
    Aug 31, 2009
    Oddometer:
    19,056
    Location:
    Silver Spring, Md
    I strongly recommend some time on Snowbum's Tech Pages and Google the $2000 O-ring on Adv rider.

    It is a very confusing subject and I can't explain it because my bike doesn't have this issue.
    Uke and SmittyBlackstone like this.
  15. Achtung

    Achtung Wicked Pisssah Adventurer Supporter

    Joined:
    Nov 1, 2002
    Oddometer:
    3,694
    Location:
    Waltham MA
    I'm fully aware of that issue. This is something else.
    Once I get the exhaust off I'll get some pictures.
    sprouty115 likes this.
  16. sprouty115

    sprouty115 Long timer Supporter

    Joined:
    May 29, 2012
    Oddometer:
    8,691
    Location:
    Providence, RI
    FWIW, I've used external circlip pliers with removable tips to pull out stubborn filters on my other bikes.
    Screenshot_20211103-114108_Chrome.jpg

    Basically I turn the angled tips away from each other, insert into the hole, squeeze, and pull.
    Uke, kbasa, SmittyBlackstone and 2 others like this.
  17. Achtung

    Achtung Wicked Pisssah Adventurer Supporter

    Joined:
    Nov 1, 2002
    Oddometer:
    3,694
    Location:
    Waltham MA
    Once I got the exhaust out of the way I was able to fish it out no problem.
    The side with no o ring is supposed to face out and was the reason the PO was not able to get the cover back on. Luckily that was the case as I'm sure he would've wrecked the motor if he'd tried to start it this way. Anyways tragedy averted.
    62D57A9C-A36F-435D-8E00-B32E171C6F0C.jpeg
    Uke, kbasa, SmittyBlackstone and 5 others like this.
  18. Disston

    Disston ShadeTreeExpert Supporter

    Joined:
    Aug 31, 2009
    Oddometer:
    19,056
    Location:
    Silver Spring, Md
    @Achtung, We have these issues when years get involved. Airheads were in production for a long time, 25 years I think. I'm not sure but I think that filter you show had or should have the rubber tip on both ends. It is called an O-ring even if not round. I think the O-ring from the end inner most is still in the bike. It is stuck at the bottom of the long tube. Fish it out.

    My bike is an older version and I don't have these issues so maybe somebody who does know will straighten me out.
    raywilson likes this.
  19. Disston

    Disston ShadeTreeExpert Supporter

    Joined:
    Aug 31, 2009
    Oddometer:
    19,056
    Location:
    Silver Spring, Md
    What's at issue is the length of the filters. BMW used 4 different filters but they come in only two lengths. There's non-cooler and cooler filters. Either one is either split or not and has that hinge but they are only two lengths. They all have o-rings at both ends.

    Now that we have mentioned the filter lengths we are ready for the gotcha. The shims and O-rings at the cover end are the important part.Do you have all the parts that came out originally? When the filter was removed? Maybe not because you didn't remove the filter.

    The ,etal shim, gasket and large O-ring at the cover will determine how the oil filter works. With the wrong set up the engine will not get oil. Yes this is why we call it "the 2 thousand dollar O-ring".

    I've gotta go again. i'm trying to put as much info in here as I can but I'm at work. The issue is not solved until you measure the depth of the filter and what sort of stack you need.
    SmittyBlackstone and raywilson like this.
  20. Disston

    Disston ShadeTreeExpert Supporter

    Joined:
    Aug 31, 2009
    Oddometer:
    19,056
    Location:
    Silver Spring, Md
    The most in depth discussion of the issue of the Airhead oil filter in on Snowbum's Tech Pages. I think this link takes you to the right page. If not we'll try again.

    Please tell us you are still here? If you think you have solved the problem beware, the problem is not solved by the little missing o-ring.

    https://bmwmotorcycletech.info/Oil.htm