My Barn Twins

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

  1. blaine.hale

    blaine.hale Long timer

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    I gotta appreciate just how detailed that was for something so simple. Good on you for putting that out there!
  2. AKcruiserfreak

    AKcruiserfreak Adventurer

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    Excellent write up! I love the detailed pics!

    TK
  3. Disston

    Disston ShadeTreeExpert

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    The different throttle cam profiles are for the R90S bikes with Dellortos, I thought? Or maybe it pertains to years?

    Now do it all over again with grease. :jack Really makes the whole operation a lot more fun.

    Thanks for the nice write up.
  4. aptbldr

    aptbldr easy rider

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    Thanks for that post.
    What are pros & cons for dual-cable throttle or single-to-splitter?
    Dual-cable seems simpler.
  5. fxray

    fxray Long timer

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    Thanks for the comments guys.

    Blaine, I agree with you. It really is pretty simple. That made it all the more frustrating for me when the manuals didn't cover it adequately.

    TK, Thanks for the kind words. :-)

    disston, I'm not sure about those cam profiles you mention. At first, I was eyeballing the profile on the cam in my R90/6 and it did not look progressive to me. I checked it with some calipers and it does have a slightly increasing radius, like Snowbum said. A quick look at the fiche shows that the R90/6 and the R90S use the same throttle cam. Take a look at Anton Largiader's site for a breakdown of the changes to the throttle assemblies from 1970-95.

    Yeah -- next time with grease! :lol3

    aptbldr, I'm not qualified to answer that question about pros and cons for dual cable vs. single to splitter on airheads. I don't know which has historically been better or worse. Off the top, I agree with you that the dual cable would seem to be simpler. With the few old bikes I have, I am blessed (correct term?) with a variety of throttle cable arrangements. It seems that once they are lubed, adjusted, and synchronized if necessary, that's about the end of the issues. The exception is that these lined BMW cables should not be lubed (even though the Clymer Manual tells you to do it on a regular maintenance interval -- just one more of their misnomers). I got a new pair of cables for my R90, and they are high quality parts -- well worth the money.
  6. Kneedrager

    Kneedrager Adventurer

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    Thanks for the write up! More good information for future reference for my '74 R90/6. Always fun when you find out (after the fact) that "oh that year was different from the others"...
  7. Pokie

    Pokie Just plain Pokie.

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    Funny, I've never used the supposed timing marks on the cam or throttle tube, never. When ever I put all the parts together, everything is way too greasy to see any of that. Put it in, try it, jump a notch, try it, done. If you put it all together and forget to grease it, just unscrew the top screw and without lifting the top, pump in grease with the same grease gun you used to grease the swing arm pivots with. Tighten down the top and wipe off the excess grease. Done.
  8. 190e

    190e Long timer

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    It may be a superior design but regardless of how often you clean and grease the gears they do eventually wear out. If they ever become NLA we will have a problem.
  9. fxray

    fxray Long timer

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    This afternoon, I finally did a task or two on the R90/6 that I had kept putting off. I sorted out all the wire connections inside the headlight bucket. That doesn't sound like much, but by my count, there are five separate harnesses that enter the bucket, and 36 individual wires. Still, BMW did a good job of organizing things in there with the built in clips and the circuit board. Blessings wished on Big Bamboo, bpeckm, and others who advocate using the white paint inside the bucket. It makes things a whole lot easier:

    [​IMG]

    Then I was able to wrestle the headlight into place for the first time. This is a used light that I bought a couple years ago from an MOA member in Florida. It's in good shape, but I could never get the spring clip at the bottom to engage until today. I'm not real tickled with that retention method, but I will use the tie-wrap idea as backup.

    [​IMG]

    Then I got my spankin' new throttle cables routed correctly (or so I believe), greased up the RH control, added a new rubber boot up there, and hooked up the cables to the twist grip. There are still no Bings connected to the other end of the cables, but it still felt like progress:

    [​IMG]

    As you may notice, there are still no gauges hung on there. I have them, but the trim rings were bad -- splitting at the top. I got the new trim rings, but there was another problem. My gauges looked like this:

    [​IMG]

    See the gap filled with black silicone under the trim rings? That didn't look right to me, so I had inquired about it on the forum. Renner told me that they were not supposed to be that way. A friend who has a couple of R90/6 bikes (and who just this week pulled an R75/6 out of a barn!) sent me a picture of how the rings fit on his (no gap):

    [​IMG]

    Renner had also kindly provided a link to this instrument repair article which is well written, so I followed that to take my gauges apart to see what was up with that gap:

    [​IMG]

    [​IMG]

    [​IMG]

    Pretty soon I was using a variety of implements of destruction to try to eliminate that black gunk.

    [​IMG]

    I'm still not sure why it was on there, but it looks like the bezels and the glass faces had come apart at some point and were glued back into place with a thick bead of the stuff. I think I can scrape them down and re-glue the bezels. If not, I will be looking to see if I can find a replacement housing (eBay prices for these are scary high). Meanwhile, I think I will replace all the light bulbs inside here just on general principles.

    I bit the bullet and ordered new clutch, brake, and speedo cables today. I figure I'll keep the old ones as spares. I also pondered buying a Nippondenso starter motor, but decided to have a look inside the old Bosch. Once the starter motor is back in place, I can hook up a battery and see where the smoke comes out. All my other wiring is complete and routed where it should be.

    That's it for this time.

    Ray
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  10. kenbob

    kenbob Gnarly GnOOb

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    Quote by Ray-

    "At least I know what my options are.
    • Keep the dents and the original paint and just ride it that way.
    • Drop in another $400 to $600 to make it pretty, but lose the original paint.
    • Do the first option, but buy a tank bra to hide the dents."

    Ray - Awesome report you are doing for the collective here !

    I bought my R75/6 from a woman owner -her Father had purchased the bike new and had given it to her for college . At the time of the sale to me , she was in her late 60's and Dad had passed quite a while back . When I was looking the bike over , in her driveway , I asked about these scratches ....

    [​IMG]

    She said " I was so emotional , leaving home for the first time and my Dad had just given me the bike of his dreams . Had it all packed in a friends pickup , for the ride from Spokane to California. Started to rain in Oregon and we jumped out to cover everything / was pouring and we got in a big hurry / so careful about the whole tarping process , but never noticed the metal hook on the bungee , till we arrived at my new college home "

    She said in the years since that happened ( late 70s ) she always thought of her Dad , when she saw those scratches on the front fender .

    I promised her I would never paint it . I reckon , I just like the history and the story .

    Plus I like the fact that a human in Germany , painted on those pinstripes and they are not absolutely perfect !


    Carry on Ray
  11. fxray

    fxray Long timer

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    ^^^ Thanks, kenbob, that's a great story. I agree with you about the hand painted stripes from Germany.

    In addition to those three options that you quoted, there may be a fourth. That would be to buy a used, but dent-free tank in original black paint/white pinstripes. I may have a line on one; we'll see how that works out.

    Ray
  12. kenbob

    kenbob Gnarly GnOOb

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    That 4th idea works also ...

    In the back of my teeny brain , I keep thinking this is my tank, this gal is painting back in 1976 .

    After all , this is my color !

    [​IMG]

    Sure would have been something to have a new one then .

    Keep on Keepin on Ray -we love what your doing
  13. fxray

    fxray Long timer

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    ^^^ In my opinion, that's your tank she's striping for sure! I challenge anybody who disagrees to prove that I'm wrong. :lol3

    I love the video that's the source of that image.
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  14. fxray

    fxray Long timer

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    Last update, I was messing with the gauge pod. I wound up starting a separate thread on that to ask about glue. That thread is HERE. I think the pod will survive. I am letting it sit under a chunk of steel for several days while the GOOP glue cures out.

    [​IMG]

    [​IMG]

    I had also ordered some cables. I opted for the OEM stuff and got them from Bob's BMW. They would have been a little cheaper if I had ordered the Featherlight cables from Venhill, but I was a little concerned about correct fitment. Venhill is a good supplier and I inquired about the inner and outer cable lengths. They responded quickly, but the lengths were enough different from what I found on the bike to make me decide not to go that route. I'm pretty sure they would have made me some custom ones, but I did not want to mess with it.

    I had learned from one of Pokie's posts that there is a felt insert on the cables to keep out the dust and dirt. Here's what those look like:


    [​IMG]

    You can see that the old one on the right has been doing its job over these past 42 years. The new little piece of felt on the left cost about $5.00, but is probably worth it for the precision with which it is made. Here it is fitted inside the thimble of the clutch cable (there is a similar setup on the front brake cable):

    [​IMG]

    These stainless steel inner cables in the Teflon lined sheathing have very easy action and never need lube. I got them all installed this afternoon, with just one glitch. This is something disston has mentioned several times, so I was forewarned about it. The swaged cable end needed some work. This was as far as it would fit into the barrel at the lever:

    [​IMG]

    Note the hex-shaped swaging. I used a little grinding wheel in my Dremel Tool to make that more rounded, being careful not to nick the cable. The end needs to fit freely and be able to swivel, or the cable end will break fairly quickly in use. The clutch cable end was not like this -- it was fine.

    Here it is in place. Note how the back edge of the cable end stands proud of the wire cable. That wanted to catch when I was trying to install it into the barrel in the lever, but it finally fit:

    [​IMG]

    I used a lot of white lithium grease on the pivot points.

    With the cables installed, all the holes were filled in the rubber block under the fuel tank. I could finally put that fancy red tie-wrap back in place:

    [​IMG]

    So it's almost back the way it was before I started messing with it . . . only different.

    [​IMG]

    When I say the cables are installed, I'm using that term rather loosely. They're routed and are hooked up properly at the handlebars. There are just a few minor components missing on their other ends (brake M/C, gearbox, carburetors -- you know, little stuff like that :lol3 ).

    On another note, a friend happened onto an R75/6 last week that had been sleeping in a barn. It just happens to be black with white pinstripes, and has the larger tank like on my bike. He prefers the smaller sport tank, and has had a nice one in blue for some time that he wants to use. He also has the matching rear fender. So . . . he was going to put the black tank (and probably the fenders) from his recently acquired barn bike up for sale on eBay. I wound up with the tank and brought it home tonight. Ain't that grand how that got me around my dent problem, yet I still have original BMW paint?

    The roundels are faded and worn, but I may want to keep them like that. If not, I know where to get them now:

    [​IMG]

    The knee pads are split and cracked on both sides. I know there is the possibility of rust underneath, but I am hoping for the best. Looks like I will get to change out a pair of these after all:

    [​IMG]

    There are even some minor scratches in the paint. I can touch that up and call it patina.

    [​IMG]

    I just don't like dents -- and there aren't any in this tank! :wings
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  15. washpark

    washpark Adventurer Supporter

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    Looking very shiny. The engine, wiring, and frame look stellar. How many hours so far?
  16. fxray

    fxray Long timer

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    ^^^Well, I didn't keep track. Maybe the best answer would be not enough. It should have been done a long time ago, but I only work on it when I feel like it. That sort of happens in spurts. Others on here have bought a bike, reworked it beautifully, and ridden thousands of miles on it while I have been fooling around with this one.

    Every time I start on some aspect of the project that I haven't done before, I do a lot of on-line reading, then read the Clymer book (for what it's worth), and the FSM (worth even less than Clymer), then get input from the inmates. All that takes time, but it is part of what I enjoy about the process. I keep pretty good records of what I have done, and even this build thread is sort of a record. If I do another airhead, it would go at a faster pace.

    The friend who recently supplied me with the fuel tank I mentioned has reworked and sold a 1974 R90/6. He now has a '75 R90 (verrrrry nice, and soon to be for sale) and a '76 R90, and a 66 R60/2, and the R75/6 from which I got the tank. He works a lot faster than I do. All this, and he's mainly a Triumph guy. Here's the last one of those he finished:

    [​IMG]

    He is very detailed and quite a perfectionist. Still, he knows how to git-er-done. Me, I sort of drift along and take my time. It's all good (I guess).

    Ray
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  17. bpeckm

    bpeckm Grin! Supporter

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    Dam tootin'....... it's ALL good!

    I can't imagine you were implying that your friend is more detailed and a perfectionist than you..... :-) We all appreciate your dedication to the details, and logging it all will be a help to many of those who will come after us. Well done, I say! After all, it IS the journey that counts. Some journey by bike, some journey in the garage.....
  18. fxray

    fxray Long timer

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    ^^^Hi Bob.

    I hope you are getting in some good rides on that conversion. I'm glad you got it done, but I do miss reading your in-process build thread.

    As far as the guy who supplied the dent-free tank, we have similar yet slightly different attitudes toward these old bikes. For example, he would say that life is way too short to lace and true your own wheels when he knows a guy who does that fast, cheap, and well! I enjoy the process of doing it myself.

    He'd prefer to buy new hardware as needed, while I spend lots of time reworking the old bolts, nuts, and washers, just to preserve the original content. While I mess around with stuff like that, he is way more productive.

    In any case, I sure enjoy conversations with him. It is almost crazy to meet a guy who has the same eclectic mix of old bikes, right down to the age and model (though his are all one year newer than mine) -- '64 and '65 Triumph TR6R, '71 and '72 Honda CL350, '74 and '75 BMW R90/6 -- what are the chances?

    So -- that tank just started its white vinegar soak this morning. I plan to do the exact same process as the one I just finished.

    [​IMG]

    My gauge pod has been sitting on the bench to let the glue for the reattached lenses cure thoroughly. I got the trim rings back on today, and they came out pretty well. I posted some pictures on that in the other thread, but here's one showing the trim ring gap closed up:

    [​IMG]

    While it was apart, I was going to replace the 8 light bulbs inside the gauge pod, but Wirespokes advised against it. I have read that just pulling the bulb holders out of that flexible printed circuit board can cause damage, and those boards aren't available anymore. There is, however, a new LED version by KATDASH due out in October that sounds promising.

    I did at least want to check all the light bulbs, so I looked around for some pin-out information on that plug for the gauge pod, figuring there must be an easy way to check the bulbs in situ. I found a really nice color schematic that someone had posted specifically for the 1974 R90/6. It shows the detail of the pins. I snatched the piece of it that shows the pins and included it here. See the 8 bulbs, and note the pin-outs numbered 1 thru 12:

    [​IMG]

    The numbers, of course, agree with the numbers molded into the rubber plug on the bike's wire harness:

    [​IMG]

    On the schematic, and on the picture of the plug, you can see that locations #9, 10, and 11 are empty. That helped me orient myself to which pin fit where. This was helpful, since my printed circuit board was upside down and on the table, away from the bike. It's also reversed (a mirror image) due to being the mating part.

    Anyway, to make it easy on myself, I made up a little table with the info from the schematic. After I was sure it was right, I typed up a copy. I think it may be useful in the future:

    [​IMG]

    Before I went applying 12V willy-nilly, I used my ohmmeter on each of the pin combinations to verify that there was some continuity, with the light bulbs offering resistance in each combination.

    That done, I set up a test battery. I added a 15A in-line fuse to prevent fireworks. That turned out to be a good idea, because I managed to touch something wrong and blew the first fuse. With that out of the way, it didn't happen again. :brow

    [​IMG]

    This is a failed battery from my Triumph, the failure mode being a leak around the negative post that let the acid out of this absorbed glass mat battery. That ain't supposed to happen. I think there is also a bad cell internally. This battery caused the one and only trailer ride of shame that the old TR6 has endured since I got it back on the road.

    [​IMG]

    The reason I mention that incident is that it happened back in May, 2015. Since that time, the Scorpion battery has been sitting unattended on a shelf. Today, well over a year later, I pulled it out of the box and it still showed 13.1V as a no-load charge level. I stuck it on a battery tender and it went to the green light in less than 15 minutes. It will do fine for testing circuits on the BMW, though it won't be big enough to spin the engine with the starter. Scorpion refused warranty because it was used in a "custom" application. The Scorpion battery's strong point though, is that they will hold a charge for a long time sitting unattended. I have a slightly larger Scorpion AGM in my CL350 that has been in use for about six years. It will sit all Winter without a battery tender and still fire up the bike in the Spring.

    So, back on topic -- I applied voltage to each pin combination and each of the eight bulbs sprang to life for the first time since 1998. Here, I was on pins #3 and #7:

    [​IMG]

    . . . and the tacho and speedo illumination lamps were doing their thing:

    [​IMG]

    The reason I wanted to save this little chart for future use is that it is a way to verify a bulb or socket fault without taking the pod apart. For example, suppose the neutral light quits working and it may be the bulb. If you put voltage between pins #12 and #6 and the bulb lights up, look elsewhere.

    Also, of course, if you have a used pod that isn't on the bike, this is an easy way to test all the lights without venturing inside the pod.

    Ray

    Disclaimer: I believe there were wiring changes in other years of the airheads. This info will be fine for a 1974 R90/6 in stock configuration. Beyond that, use your own best judgement to prevent setting your bike on fire.

    Also an afterthought: this pin-out info may or may not already be listed in the Clymer Manual. If it is in the Clymer, it may be shown correctly or incorrectly there. I have sort of given up on that book.
  19. fxray

    fxray Long timer

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    Last time, I was talking about the instrument pod. After finding that all the lights worked, I spun both gauges by hand, using a .100" square drive bit in a nut driver. The action seemed smooth and easy on both the tach and speedo. Counterclockwise (anti-clockwise) made the needles swing in the proper direction. Then I stuck the bit into my variable speed electric drill and spun them. They both gave steady readings at various speeds, with no needle waver. The worm drive gears looked clean and seemed to still have plenty of lube. It may be a mistake, but I decided to leave well enough alone. I reassembled the pod and put it back onto the bike. I'm happy with the new trim rings.

    [​IMG]

    That pretty well finished up the front end, so I started worrying about the starter motor. I've really been torn for a long time as to whether I should use the old original Bosch or buy a Nippondenso. I know several people on here favor the Valeo starters, but I read enough negative comments that I eliminated that choice.

    My existing starter looked pretty rough because of the brake fluid bath that it received while in the barn. However, I decided to at least see if it would spin up. I hooked up my bench battery test leads and gave it a try. It tried to spin, but blew the test lead's in-line 15A fuse right away. I considered going to AutoZone for some heavier fuses, but opted instead to just hook up a battery charger.

    [​IMG]

    I clipped the black, negative lead onto the starter case, and the red, positive lead onto the battery cable stud on the solenoid. The little red wire there on the table was a jumper to the spade connection on the solenoid. So -- the Bendix works just fine, and the starter spins up with no undue noise. With the Amp ring of my multimeter snapped around one of the leads, the meter was showing 26.8 DC Amps when the starter was running. Does anybody know if that is high, low, or normal for this no-load test?

    Perhaps another mistake, but I decided that if it ain't broke, I won't fix it. I realize that it could likely benefit by having the carbon dust cleaned out and by getting some fresh lube into the bushings, but on the other hand, it seems to work just fine. I started to clean it and sand it down for paint, but decided life is way too short for that. I sealed up the nose with several layers of masking tape, and ran it through the blast cabinet.

    [​IMG]

    If we ever get below 98% relative humidity, I'll shoot it with some black paint. I still have to finish painting the tunnel area on my original fuel tank and get it out of my way. Meanwhile the new (used, but dent-free) tank is about done soaking in vinegar to derust the inside and strip the factory red coating. The big brown truck dropped off two POR-15 kits this afternoon, one for this R90/6 tank and one for the RD250 Yamaha in the basement.

    Once I get the starter back into place, I can test all my wiring. Then the next thing will be to fool around with the gearbox. I have all new seals for it -- including that one behind the output shaft, and the kicker shaft too. I hope I don't mess those up, because I did spend a lot of time cleaning this thing. Well, at least it was clean the last time I saw it.

    [​IMG]

    [​IMG]

    I think I still know where I stashed it so long ago!

    Ray
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  20. bpeckm

    bpeckm Grin! Supporter

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    Your posts continue to amaze and awe... little things that I skim over, you cover in detail with photos, analysis... thank you once again for your attention to detail! Good job, mate!