My Barn Twins

Discussion in 'Airheads' started by fxray, Feb 26, 2015.

  1. chasbmw

    chasbmw Long timer

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    There should be a 4" long rubber sleeve that accommodates the wire for the points and helps to further seal the points cavity. I found that it works to a degree, but when fording a river the engine cutout, due to water in the points, this was back in 1978, I went electronic after that!

    If the pivots on your centre stand are in reasonable condition then the stand is fairly easy to use, much easier than the later 81-84 bikes.
    #41
  2. CafeDude

    CafeDude Ride to eat.....

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    Don't toss that fairing away! With the connected backstory, someone will want it bad. I sold a similar one, with zero 'provenance' though for $400 on eBay. I was shocked. I would have been happy for someone to just come and take it away. I only paid $500 for the bike....would have paid more if that big ugly fairing wasn't on it! LOL.

    Apparently there are people out there that want these things.
    #42
  3. r60man

    r60man Long timer

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    Say what you will about the placement of the ignition system but I can honestly tell you that I have ridden at least 20,000 miles in the rain on a /6 and never once had an issue due to rain. One time on the NY state Throughway it was raining so hard that all I could see were the light of the car in front of me, I stayed with it too scared to merge, slow down or do anything. Missed my exit, but I survived. And the bike ran perfectly through it all. Same one as I have now. Simply not an issue that I have ever heard of. I am sure some will pipe in, but I have never had an issue.
    #43
  4. Tourbus

    Tourbus Lost but not worried

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    These are tough old brutes. I have one bought new 3-22-1976, put 134K on it between then and 1995. Still have it. Installed decompression plates under the cylinders and a second front disc. Braking was marginal at best with one disc. Engine still has all original internal parts. Trans rebuilt twice, tend to ruin the bearings if lugged running two lane roads in 5th gear.
    #44
  5. fxray

    fxray Long timer

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    chasbmw: Yep, I have the rubber sleeve. I read somewhere that people have problems where the strip seal abuts that sleeve. It's good to hear that it mostly works. I won't worry too much about it, and I will try not to ford any rivers with it. My centerstand is in good condition, and I just got it powdercoated. Nobody even broke off the tang in all these years, and I do understand how it is supposed to be used. The people on the MOA forum had a thread once that went on for 6 pages about BMW sidestands and centerstands, but that was in tihe oil heads section. There are also several threads on ADVrider about stands. Airhead side stands. Some of it gets pretty bizarre.

    Maybe I read too much, but this thread was talking about the strip seal.


    CafeDude: I plan to hang onto the fairing. I was mainly hoping to find out it was worth a lot of money so I could razz my buddy who sold me the bike. So far, it's just rare enough to be a novelty.

    I keep telling him that when I get done with his old bike he'll want it back so bad he'll pay me $25K for it. He said, "If you're gonna dream, dream big. Pretend it'll be $100K -- either way, it ain't gonna happen!"

    r60man: Thanks, that's reassuring.

    Tourbus: My bike has the decompression plates on it already. I guess I'll keep them in place? I haven't measured the thickness yet.

    This bike makes 3 total now where I have the first year, undrilled disk brake. It just sort of happened somehow. The other two are Japanese.

    It's good to hear you got good service from your bike. Lugging in top is not a good idea for any bike, so I try to avoid it.
    #45
  6. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    Actually you have the old /5 (and I think early /6) breather housing in your picture. It'll work with the new reed-type breather valve, the later housing is "new and improved".

    Original /5 housing and straight hose. For years the hose was not available and the best "nearest fit generic hose" worked so-so. The correct hose is now available.



    New and improved housing and hose:




    Dang. You did. And that is outright copacetic. :thumb


    --Bill
    #46
  7. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    Darn straight and worth repeating.

    Craig Vetter was an American original and still is and active force. Love 'em or hate 'em, he was one of the firsts. My bike had a early hand-laid 'glas (not vacuum-formed ABS plastic) Vetter Windjammer for years. After 35 years it needed some major structural rebuilding, and I replaced it with another "Original"-- a used 1985 Hannigan fairing, handmade at the time in Canada, Eh.

    I guess there is a certain appleal to riding a nekkid unfaired bike, but from a pragmatic standpoint, it's much nicer not to be buffeted and beat up by the wind. The Hannigan is nice because it is so slippery and aerodynamic.


    Here is the Craig Vetter website: http://www.craigvetter.com/index.html


    What a great story!

    I didn't see a link to it at the Vetter website, but here is my favorite Vetter image of all time. Notice the names.


    --Bill

    Attached Files:

    #47
  8. fxray

    fxray Long timer

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    Bill, Thanks for the info on the breather. I had no idea of that change. The one you pictured looks like it might be a little better for oil control. Ideally, I think I'd rather have it vented outdoors, but not badly enough to cut a hole in the cover. I will remember this for the future, and see how the one I have works out, but that other setup does look like an improvement. This '74 /6 seems to have several /5 carry-overs, like the switch gear on the handlebars for example, yet the bike was built in June, 1974.

    Glad you like the fairing story. It kind of blew me away when I learned the history of it. It was very nice of Craig Vetter to offer that information. I assume that the headlight in the picture of the crash is the same one I have now also.

    When I got this bike, I found an ad in the MOA magazine where a guy was selling the original headlight lens, bezel, clips, etc. I bought that and also got a seat grab rail from him. When the fairing was put on, there was one of those rubber cups put over the front of the headlight bucket and then it had a couple wraps of tape to hold it in place. When I removed the tape, the paint came with it. Oh well! I wound up getting the bucket blasted and powder coated and it looks just like paint. I still need to pick up some turn signal stems.

    If not for the way the mounts screw up the paint/powder coat on the frame, it would not be too big a deal to put the fairing, crash guards, etc. on or off as desired. Same with the seat grab rail -- four bolts and the backrest goes back on there, so I'll keep that around too.

    Anybody got an opinion on my timing chain & sprockets? (scroll up a little to see pictures). My inclination is to button it up with the new seals and gaskets and see how it goes. On the other hand, it seems a little crazy not to change it out while all is open.

    I got things a little out of sequence. While the back end was apart, I should have tipped the engine vertical and pulled the sprockets and the cam. I hate to disturb the back end now, and I'm a little goosey about getting that cam sprocket spaced correctly if I should pull it with the cam in place. This is one of those things that makes me wish I had gotten the engine running before I pulled it apart, so I could have seen how stable the timing marks were with a strobe. Coulda' shoulda' but didn't.

    Ray
    #48
  9. chasbmw

    chasbmw Long timer

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    I really like the plain jane /5 switchgear, it just makes so much sense.
    #49
  10. fxray

    fxray Long timer

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    I agree, but I haven't ever had a chance to try them yet for real. :lol3

    I just checked the photobucket link in your signature. You have some seriously cool pictures in there!

    Bill: I see you got your picture to kick in. Those must have really been some times over there in Rantoul back in the day. I notice that in your picture, Carol had on a similar pair of cutoff jeans as when she was posed behind the fairing. Must have been uniform of the day back then. Superdog probably had a good life too!
    #50
  11. chasbmw

    chasbmw Long timer

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    Thanks,

    The black 75/6 in the Srilanka, India, afgan pictures were with a75/6, I think it was a 74, certainly had the old switches, much more natural to flick your thumb up and down!
    #51
  12. fxray

    fxray Long timer

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    One of the side jobs along the way was the seat. The original foam was still soft and comfortable, and the cover was in pretty good shape:

    [​IMG]


    In use, the Krauser rack rubs against the plastic trim whenever the seat is opened, and that had taken a large bite out of it:

    [​IMG]


    That back rest would be comfortable for two-up riding, but I like the looks of the original grab rail way better. I found one that didn't fit at all right, but it turned out that the rear legs were bent. They are pretty soft steel and bent back without cracking. Actually, it was probably from a /5 SWB bike and thus the misfit on my /6.

    The pan was solid, but had a lot of rust on it. Since this project started as a cleanup only (before project creep set in) I took the seat apart and decided to strip the pan and rattle can it. The pan is too long to fit my HF blast cabinet, but a friend has a bigger cabinet that he lets me use on occasion. I don't know if his blast media was needing replacement or if the paint on these bikes is just very tough, but I blasted on it for over four hours and was barely over halfway done.

    I took it back home and went after it with a fiber disk on my sander. That went a lot faster. With the bulk of it done, I went back and bead blasted the nooks and crannies.

    Then I shot it with some Duplicolor rattle can primer, black, and clear.

    Later, I found there is a good local shop that will blast and powder coat almost anything. He likes motorcycle and street rod work the best. Had I known of him sooner, my seat pan would have gone there for sure.

    The original seat cover was in nice shape except frayed in several places around the bottom edge where it stretches over the pan. BMW put some kind of tape on the raw edge of the pan, but it was deteriorated and the pan was cutting / wearing through the cover. I found this car door edge welt at AutoZone:

    [​IMG]

    [​IMG]

    [​IMG]


    This stuff is about the right size and has adhesive already inside the U shape. Just press into place and cut to length. It is pretty flexible and sticks easily. You are supposed to give it a day or so to bond. It worked even where the pan is irregular and made a protective edge for the seat cover material:

    [​IMG]


    I only replaced some of the rubber parts. I cleaned and reused the cushion on the seat pin, and most of the little pads that rest on the frame rail. BMW is proud of these little bits and the price adds up quickly.

    [​IMG]


    I reused the old foam, but did not glue it to the pan. I don't know why the factory felt the need for glue, except it may have kept the foam and pan together while in process. The pan has a big hump in the middle and can't really go anywhere.

    I tried to reuse the little M3 bolts and nuts, but gave it up as a lost cause. When new, these are long enough to assemble through all the layers. Then you cut off the extra. The old ones were too short since I added the edge welt. I got some new tiny bolts, a few of the rubber pads, and new trim strips from Bob's BMW.

    Here's the way it is now. It should work for a while. There's probably a new seat cover in my future, but it's nice to use the original as long as it holds up.

    [​IMG]


    The back rest cleaned up nicely. I imagine my wife will want that on there before she will go for a ride, but that only takes a couple minutes to switch out.

    Ray
    #52
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  13. CafeDude

    CafeDude Ride to eat.....

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    Awesome job! That seat looks like new.
    #53
  14. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    Good job on the seat refurb.

    The backrest is a Reynolds backrest, very popular back then and common nowadays. You found most of the pitfalls (prattfalls?) of seat work.

    Hans Lowe (Hucky's Spare Parts) has the seat trim strip and those &^#%$ teeny-tiny M2 (or were they M1.5??) bolts. Sargent Seats has quality repro seat covers.

    http://bmwhucky.com/
    http://www.sargentcycle.com/

    --Bill
    #54
  15. fxray

    fxray Long timer

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    Thanks for the comments, Bill and CafeDude. Those are M3 bolts and nuts, but still tiny.

    I may have found one new seat pratfall that I didn't mention. I stuck my hand in under the foam to peel the glue loose from the pan. When I got it apart, I was wondering why BMW had it marked underneath with red paint. Then I realized that was blood, as in my blood. I'm not sure how it happened, but my DNA is now embedded in this old bike. :lol3
    #55
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  16. Disston

    Disston ShadeTreeExpert

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    In the earlier years of Airheads a model years production begins in September of the year before. Therefore 1974 bikes were built September 1973 thru October 1974. 1975 production begins in September 1974.

    Most changes occur at model year changes. For example 5 speed gear boxes start with the 1974 model year. All 1974 bikes have a 5 speed trans.

    A few changes took place during a model years run.
    #56
  17. OLD GREEN

    OLD GREEN Long timer Supporter

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    Your doing a great job, it's fun watching this bike come together!:thumb:thumb
    #57
  18. fxray

    fxray Long timer

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    Thanks for the comments.

    Here's a bit about tools. I have been buying this 'n that from
    Easy stuff I made myself, like this torque reaction bar for the flywheel:

    [​IMG]

    For some things, it helps to have friends. One guy I know is a retired tool maker, CNC programmer, etc. He is pushing 80 years of age and still rides his R1200RT like a young guy -- quite a remarkable person.

    Years ago, he inherited a South Bend Lathe from his patternmaker father. The lathe dates to 1935 and is as nice to look at as any vintage motorcycle. With this and a tabletop mill, he has helped me out on this project by making some tools that I wanted. I mentioned the shock absorber compressor fixture earlier, but here are a couple more.

    For the swing arm, I got a 3/8 drive x 27mm deep well socket, did some measuring, and made up a little sketch. After turning the tip of the O.D. and milling a slot for a 6mm allen wrench, it fit just right for the swing arm pivots / jam nuts. I can keep the pins from turning while I torque the nuts:

    [​IMG]

    [​IMG]


    Then I was studying Snowbum's article on wheel bearing preload. I decided his method had merit, so I wanted some axle spacers made up.

    One of the guys in the local MOA Chapter found me a nice short length of cold rolled round steel bar stock 1.5 inches in diameter. This bit of AISI 1045 steel was good enough to use without turning the O.D. -- nice stuff, and even better, it was free.

    After some more measuring and sketching, and a trip to my machinist friend, I have these:


    [​IMG]

    Since I have the one-year-only 14mm dia front axle, the job required two setups. The spacer for the front wheel is 2.20 inches OAL, with a nice, slip-fit 14mm bore through the center. The rear wheel spacer is 3.50 inches OAL, and has a slip-fit 17mm bore.

    They are both drilled and tapped for a #6 screw to pinch one end of a piece of heavy fish line.



    You can read about how to use these in the wheel bearing section of Snowbum's page.


    Some people say they can't read his articles, but I think he has posted a lot of very good information. My method with these articles is to find the part I want, then copy and paste it into MS Word. I immediately use the paintbrush tool to strip off all highlighting and to make the fonts a uniform size, stripped of bold or underline attributes. Next I delete all but one instance of repetitive text. That's all quick and easy -- the hard part is to retype the sections that are in all caps.


    Once I have done this, I pretty well have a grasp of what he was saying, and have captured the part that is relevant for me. Plus I have a good reference document that I can reread without having my eyeballs explode.


    I respect his copyright -- this is for my own use only. I am grateful to him for putting all his material out there; I just can't handle the format.
    #58
  19. mr jazzbo

    mr jazzbo Adventurer

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    Ray,

    You never cease to amaze me with the tools you come up with. I followed your 1964 Triumph rebuild and it seems like your magic is still working!

    Jim
    #59
  20. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    Nice tools. Mine tend to be more "improvised". And these basic tool mods and designs have been around for years and may even be the product of parallel (d)evolution.

    And I think that everybody in the known 'Verse has a genuine "Paul Tavenier Points Tool", or ought to.

    I kibbitzed one a few years back that "zeroed out" the 0.016" point gap so all you had to do was set the point gap by the tool to -0- to get a 0.016" gap at the points cam. Lazy is as lazy does. ;)

    --Bill
    #60