My 1974 R75/6 story, with plenty of pics!

Discussion in 'Airheads' started by crazydrummerdude, Jan 1, 2010.

  1. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

    Joined:
    Nov 28, 2006
    Oddometer:
    7,652
    Location:
    El Segundo, CA
    This is for those of you not on the MOA forums.

    Well, it’s cold, dark, and a little snowy outside right now, so I figured it was time for a write-up of my 1974 R75/6 and my introduction to the BMW motorcycle world.

    Fall 2004
    As mentioned on my R90 thread, I didn’t even know BMW made motorcycles until my friends parents became my new lawncare customer(s), and they had two old, broken motorcycles in their garage under boxes and behind “junk.”

    [​IMG]

    One of us informed the other that a deal could be made.. and after a small wait, the deal was struck.

    December 2, 2004
    I drove my Blazer to my grandmas to pick up my Silverado/trailer and go pick up my new motorcycle. The Silverado was parked in the field behind the shed because the shed was full of other crap (we'll get to this). I started up the Silverado and drove in a big half-circle before I got completely stuck in the mud.

    So, I:
    went into the shed to retrieve the other trailer inside.
    had to pick up and move about 30 sheets of 4'x8 and 4'x12' drywall that was sitting in the middle of the shed for a different project.
    had to unload approximately 50 computers off of the other trailer.
    had to carry the trailer out to my Blazer.

    This trailer had a single axle, no gate, a license plate that was several years expired, no chains, a questionable wiring harness, and those dinky 12”(?) wheels/tires. Whereas, the stuck-in-the-mud trailer had 2 axles, a gate, clear plates, chains, good wiring, full size wheels/tires.

    I drove out to the customers house. Their son and I determined the motorcycle was too heavy for the both of us to lift. The "ramp" we rigged was a thin piece of plywood, but didn’t work because the R75’s tires were flat. So, we called our friend Jim and his girlfriend to come help. The three of us males were finally able to get it on the trailer, and strap it down.

    I took it by my dads work so that he could admire it (25 years prior, he had a similar year R75/5 toaster tank BMW), and by my jealous friends work for a little bragging. Haha.

    It was getting a little late, and I dropped it off at my grandmas shed and went home to do research. I remember describing the engine to my brother on the phone as looking like a briefcase with cylinders sticking out the sides.

    Winter 2004 / Spring 2005
    I removed the fairing, changed out all the fluids, replaced the battery, coated the tank (with Kreem, yeah, I know), replaced the petcocks, rebuilt the carbs, and cleaned the bike a little bit in the mean time. I also titled it.

    May 16, 2005
    I was hanging out at my grandmas with my brother when his friend Mark stopped by and after some prodding, he convinced me to drive home and get the gas tank that I had waxed. I brought it back, and after a very small amount of effort, I had it running for the first time. This machine sat for 20some years with gas still in the tank, and it's able to start up with very little actual mechanical work. I put 12.8 miles on it riding it around the neighborhoods near my grandmas.

    The following year

    I rebuilt the master cylinder. I bought the appropriate headlight parts and turn signals along with a few special tools. I sold my fairing. I did general work on cleaning and maintaining the bike.

    August 26, 2006
    As I was pulling into my driveway, the motorcycle died. I attempted to restart it, but the only thing that happened was the blinker blinked once, and quickly dimmed out.

    Afterwords,
    • there was no response from the starter button,
    • the neutral light did not work,
    • the blinkers wouldn’t do anything more than flash once,

    I did the following to troubleshoot the problem;
    • I replaced the starter relay with a brand new one, but nothing changed, so I re-installed the old relay.
    • I replaced the fuses with new ones, but nothing changed, so I re-installed the old fuses.
    • I tried to charge the dead battery with a charger that was supposedly “too powerful,” and may have “fried” the battery.

    Of course the day that happened, both my mom and my grandma asked "Oh, you got the motorcycle running?"

    It sat in this condition for a little too long before I was fed up with troubleshooting, and decided to take it to a shop. In this time I finally got a digital camera. Here is a picture of how it was as of about the beginning of August 2006.

    [​IMG]

    This is about 50x better than it was when I recieved it. Yet, notice:
    the Vetter Windjammer wiring harness just hanging out of the bottom of the headlight.
    the semi-bent posts where turn signals should be.
    the shredded fork gaitors.
    the rust all over and the dirt.
    the rusty/green spokes.
    the tires:
    [​IMG]

    November 9, 2006
    Iit passed inspection.

    November 13, 2006
    Icensed it.

    Mid-December, 2006
    About 1000 miles accumulated.

    May 4, 2007
    I'd ridden it about 2000 miles. I changed the oil and filter in 'er.. a little premature, but I wanted to examine if there were any metal shavings in the oil. None.

    July 14, 2007
    First several-hundred mile road trip. Stopped at my family farm for fireworks.

    [​IMG]

    September 2007
    Installed new carb floats and removed dried/cracked fuel filters.

    Early October 2007
    Attended the Falling Leaf rally in Potosi, MO.

    [​IMG]

    October 20, 2007
    Rebuilt the speedometer.

    [​IMG]

    October 21, 2007
    Speedometer cable broke, so I replaced it. I swear it had nothing to do with my rebuild! Haha.

    [​IMG]

    October 28, 2007
    It wouldn't freaking start that morning. So, I adjusted the R75 valves with my new metric feeler gagues and set the clearances as per the Clymer. As they were, one intake was probably 1.5+mm, the other was slightly less, and neither exhaust valves actually closed. Ridiculous. Surprising it even ran. I also noticed the carbs were a bit cockeyed, so I made them more vertical, and made sure all the connections were tight. The ride home was like a whole new bike. Amazing difference in performance.

    December 4, 2007
    It happens to everyone. I dropped it. At least this was in my front yard. Left a funny valve cover dent in the ground.

    [​IMG]
    #1
  2. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

    Joined:
    Nov 28, 2006
    Oddometer:
    7,652
    Location:
    El Segundo, CA
    December 5, 2007
    I rode to school in the freezing rain, as I had been doing the past few days. I went to leave, and I got nothing but "ticktick" and a dead battery. My professor that I had that day walked by and I asked him if he had jumper cables. He acted like he didn't know me, and told me to contact campus security. I got them to bring me 3 different battery chargers…. and nothing. I called my friend Matt to come pick me up. So, when I was waiting, I attempted to pop-start my motorcycle in the parking lot. Twice I forgot to turn the key on. The last two times, it fired a couple times, but failed to get running. After Matt arrived, a very good looking girl pulled up and asked if we needed help. She thought it was Matt's car that had the trouble, but I explained it was my motorcycle. She said "Well, if you need anything, let me know." And she drove off. Neither of us know/knew her. Matt took me home. I got my truck and went to my grandmas to pick up my trailer. I picked up the bike, and put it in the shed there. I spent the rest of the day trouble shooting

    December 25, 2007
    I hooked the battery charger directly to the starter, with the same results. Just ticking. I took the starter off, and hot-wired it with the battery charger, and it spun freely. I took the starter off my R90 and hot-wired it with the battery charger also. It acted the same as the R75 starter. It spun right along. So, I figured I'd just go for it, and hooked the R90 starter up to the R75. I hooked the charger directly to the starter. It ticked just like the R75 starter did.

    <embed type="application/x-shockwave-flash" allowfullscreen="true" allownetworking="all" wmode="transparent" src="http://static.photobucket.com/player.swf?file=http://vidmg.photobucket.com/albums/v469/aretnap69/bmw/dec10015.flv" width="600" height="361">

    January 5, 2008
    I had some spare parts laying around, so I hooked up a new/good starter relay and the ticking continued, but it "caught" a couple times and you could hear it blup blup as each cylinder slowly turned over, but it went back to ticking.

    Winter 2008
    I had a list of things to do to the bike and accomplished a few of them, except getting it to start. I couldn&#8217;t figure it out. I just couldn&#8217;t bring myself to buying a new battery, especially knowing that the battery charger was good.

    March 8, 2008
    Forum member woodnsteel decided to come to my aide. He made the trip from Peoria, Illinois to our shop in Missouri (195 miles!).

    [​IMG]

    In preparation for this, I bought a new battery (although I previously thought mine was good), rings, and a few other things. We gave my bike a spline lube, honed the cylinders, installed new piston rings, installed new push rod tube seals, anti-seized the exhaust nuts, and installed the new battery. The bike ran A-OK again.

    March 11, 2008
    Well, my push rod tube seals were cheap after-market ones, and 3 of the 4 split, so I replaced them. I also adjusted the valves.

    [​IMG]

    Summer 2008
    Fluid changes, etc. Installed new oil pressure switch because it was leaking pretty bad.

    [​IMG]

    July 17/20, 2008
    I attempted to take the R75 to the MOA national rally. In Western Iowa, a storm rolled in. I took refuge at an abandoned gas station for a while, before heading back out in it.

    [​IMG]

    After &#8220;sleeping&#8221; under a picnic table at a rest area in a heavy rainstorm, I got stranded in Nebraska during the second day of the trip due to a faulty charging system (a rotor wire cracked) and had to abort the mission. A fellow in Council Bluffs, and a family in Omaha came to my rescue and helped me along my journey. BMW Omaha was absolutely helpless/worthless, and after wasting a few hours waiting there, I told them to forget it, and I&#8217;d be on my way. I have a lot to say about this trip, if anyone&#8217;s interested. It was ridiculous.

    Fall 2008
    I plugged my bike in every night, and could only go on rides of less than 200 miles before I&#8217;d start having trouble. One such ride was in a snowstorm in rural Missouri, where a priest at a gas station most likely saved my life after my headlight and taillight had all faded away. That sucked. I bought a new diode board, as was recommended, but still had no luck.
    I moved to finish off my school career. My brother used my truck for lawncare back home, and I parked my motorcycle in my new living room. As evidenced by the bare walls and lack of tv/computer, I am a party animal! Haha.

    [​IMG]

    It gave me time to just sit there and stare at the ol&#8217; girl.

    [​IMG]

    Also, my carb diaphragms developed a small tear and after some troubleshooting, I replaced them, and was able to reach speeds above 65 again. Hallelujah!
    I bought a large /6 tank online (a little more rough than advertised if I do say so) and installed it.

    Also, went on my first group ride. Not as scary as I was thinking.
    Rebuilt my speedometer again, as a gear had slipped on its shaft.

    [​IMG]

    ..and this little guy migrated.

    [​IMG]

    Of the ONE time I didn&#8217;t have any extra ropes/bungee cables, my left Krauser decided to abandon ship. Shortly thereafter, as I was standing on the side of the road waiting to snag it from traffic, it was obliterated by some target-fixated moron in a blue car. Everything in it was killed, including my camera and ipod. This is what was left of it.

    [​IMG]

    October 10/12, 2008
    Attended my second Falling Leaf Rally. This time, I actually had enough time to camp.

    [​IMG]

    Winter 2008
    woodnsteel to the rescue again. He graciously made the trip again with spare parts in hand. He showed me many charging system diagnostics, and when it came time to test the rotor, we found the culprit. One wire inside had broken, and it wasn&#8217;t charging my battery back up. Replaced it, charging light went off, and it has run fine since then.

    I &#8220;machined and installed some high performance parts.&#8221;

    [​IMG]

    [​IMG]

    Spring/Summer 2009
    She treated me well. She just wanted to ride. So, ride we did.

    [​IMG]

    I rode my R90 quite a lot at this time (including to the national), and my R75 got jealous. So, during a back way ride from my moms house to my house (~150 miles), as I got out into no-mans-land, a small o-ring in my left carb came apart. I was honestly so confident in this bike by now, I didn&#8217;t bring tools with me on this trip. Big mistake. The bike was running so poorly, I probably could have gotten off and pushed it up the hills I was riding. I didn&#8217;t know what the problem was, but as I had just replaced my sparkplugs, I thought it might have something to do with them.

    I stopped at a gas station, no tools. The bar next door; &#8220;Do you have any tools here?&#8221; &#8220;Sure, what do you need?&#8221; &#8220;Spark plug socket.&#8221; &#8220;Oh, no, we don&#8217;t have anything special like that.&#8221; A patron offered to let me go to his shop. I was very thankful, and suited up to follow him. As he got in his truck, he yelled &#8220;GREAT, JUST WHAT I WANTED TO DO ON A SUNDAY NIGHT!&#8221; I followed him there, and apologized for going so slow, and he said &#8220;Yeah, I thought I was going to have to throw it in reverse.&#8221; Um, ok. I adjusted my valves and gapped the plugs, and it ran like a top.

    A few minutes down the road, it went back to crap. The 2.5 hour ride took 6 hours. The bike died 3 times. After dark, the fog started. I couldn&#8217;t even see my feet or the road. The next day, now that I was at home, I found and fixed the problem in 15 minutes. She&#8217;s back runnin&#8217; fine and treating me well.

    Winter 2009
    Still ridin&#8217;. Some vintage guys have a cool, vintage look. I look like a moon-man.

    [​IMG]

    [​IMG]

    [​IMG]

    The left kneepad was coming off, so I yanked it off to not lose it.
    I think I&#8217;m going to do a rear main seal/oil pump o-ring in the next week. I&#8217;d like to repaint the large tank, as the paint on it sucks (dull gas stained black spray paint over original blue).
    #2
  3. Bigger Al

    Bigger Al Still a stupid tire guy

    Joined:
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    8,011
    Location:
    Auburn, CA
    What a great story of perseverance! Good on you for not giving up on the old girl when so many others would have. You've developed a mechanical relationship with this bike, and IMHO that makes the rides and trips more meaningful. It's kind of nice to not have a feeling of panic when things go wrong, but rather to have a solid basis of what the problem might be and how to get it resolved. Airheads are great teachers that way.:lol3
    #3
  4. stuckinoregon

    stuckinoregon never enough riding

    Joined:
    Sep 13, 2007
    Oddometer:
    56
    Location:
    Molalla, Oregon
    Love it - You just put in words what it is like to own an old motorcycle! Whats with the anvil, pic though?
    #4
  5. Cogswell

    Cogswell Spudly Adventurer

    Joined:
    Jan 3, 2005
    Oddometer:
    4,754
    Location:
    Riding with my pal Richard Cranium
    Great story thanks for sharing it, you and the bike seemed to have bonded well.
    Not all riders would make good airhead owners.


    Mike
    #5
  6. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

    Joined:
    Nov 28, 2006
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    7,652
    Location:
    El Segundo, CA
    Search youtube for "anvil blast". It's a tradition at the Falling Leaf rally.
    #6
  7. Bigger Al

    Bigger Al Still a stupid tire guy

    Joined:
    Oct 12, 2004
    Oddometer:
    8,011
    Location:
    Auburn, CA

    :clap That looks like fun!
    #7
  8. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

    Joined:
    Nov 28, 2006
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    7,652
    Location:
    El Segundo, CA
    In 2008, the fuse was burning. In the distance, we all heard a rumbling. A cruiser rider was chuggin' down that road, and when he was about as close as he possibly could be, BANG!

    He ducked hard, and probably messed his pants.. but kept on chuggin'.

    :lol3
    #8
  9. Bigger Al

    Bigger Al Still a stupid tire guy

    Joined:
    Oct 12, 2004
    Oddometer:
    8,011
    Location:
    Auburn, CA
    :poser Oh man, I'd have paid big bucks to have seen that!
    #9
  10. What?

    What? curmudgeon

    Joined:
    Oct 3, 2007
    Oddometer:
    364
    Location:
    Biddeford, Maine
    Re; anvil

    What were the rednecks famous last words?

    Hey Y'all, hold my beer and watch this!
    #10
  11. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

    Joined:
    Nov 28, 2006
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    7,652
    Location:
    El Segundo, CA
    Time flies when you're a full time student.

    Assuming the process wouldn't require any more parts than a few replaced nuts and bolts, I dug in tonight.

    [​IMG]

    Well, the friction plate and spring were below the minimum(s). So, I have to order those. The Clymer lists a "clutch plate" in addition to these two, but I can't figure out what they mean, exactly, as there's nothing labeled that way in the diagrams.

    But, with a new friction plate, should I get these resurfaced? (I can feel ridges.)

    [​IMG]

    ..and lastly; I have the older style phillips head screws covering my oil pump. What a dumb design! As with my R90, I felt a massive amount of resistance in the bolt I tested, so I figured I'd weigh my options before stripping that bolt.. I don't have access to the mini electric impact any more.

    [​IMG]

    With that said, though, I'd like to "upgrade" to the hex-head style cover. I assume that the oil pump cover plate bolt holes are tapered all the way down for the countersunk heads, so I doubt I can machine it out well with much meat left. So, does anyone have any suggestions, or newer plates for sale?

    :ear
    #11
  12. Hawk Medicine

    Hawk Medicine Coyote's Brother

    Joined:
    Jun 8, 2008
    Oddometer:
    3,304
    Location:
    NOR CAL
    Hey dude!

    I probably have the pump cover that you need.

    PM me or send me an email and I'll toss it in a box. What else you need? I'm cleaning the garage!:D
    #12
  13. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

    Joined:
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    El Segundo, CA
    ..a stock seat for my R90! :lol3

    PM sent.
    #13
  14. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

    Joined:
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    El Segundo, CA
    Last night, I checked out Southland Clutch 's ad in the airmail. Figured they might be the place to send my parts for resurfacing.

    Anyone have experience with them?
    #14
  15. Bigger Al

    Bigger Al Still a stupid tire guy

    Joined:
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    8,011
    Location:
    Auburn, CA
    No personal experience with Southland, but my 2 cents' worth:

    I had a machinist friend of mine resurface my pressure ring the first time the clutch was changed. He went through several cutting bits trying to get it done and told me that it was the hardest piece of steel he'd ever seen.

    You might want to think about replacing the pressure plate in addition to the friction plate. I had one that I reused break all of the spot welds. The clutch still worked, but slipped something awful.
    #15
  16. datchew

    datchew Don't buy from Brad

    Joined:
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    Remember the Alamo!
    Great thread CDD.

    You probably won't know until you just take the plate to a machine shop and have them assess it. Compare the cost to a replacement new one.

    hope to catch up with you one of these days. Not enough of us advrider old school "younguns" around.
    #16
  17. England-Kev

    England-Kev Long timer

    Joined:
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    3,771
    Location:
    England. Somewhere on the Canal.
    Hey CDD, thanks for sharing this with us, great read..:clap
    #17
  18. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

    Joined:
    Nov 28, 2006
    Oddometer:
    7,652
    Location:
    El Segundo, CA
    I think I'm just going to be a guinea pig for myself and ship my stuff to Southland Clutch. I'm torn, because I would really love to try machining it on the lathe.. but the friction disk replacement is the only thing keeping me from attempting it. (Hmm.. I wonder if I could machine it down, mail it to them, and have them make me a corresponding friction disk.) Now that I think about it, I was helping my friend replace the clutch in his CRX and I think the machine shop used a rotary table on a mill. I don't have one on my mill. Oh, I'm rambling again..

    :lol3

    But, I'm strongly considering going to the Spring Fling, so I may have a chance to meet up with all the advrider peeps.
    #18
  19. Detroit Steve

    Detroit Steve Homely Adventurer

    Joined:
    Feb 6, 2008
    Oddometer:
    516
    Location:
    Further...
    Save your money and time and buy new clutch plates! The friction plate 'should' work.

    I have turned those plates on a lathe like Bigger Al mentioned with the same results. Being the smarter machinist I ground those surfaces with a decent cross-hatch pattern. What happened is the clutch still slipped. Upon the third tear down what we found is plates looked exactly like yours or my buddy's on his first tear down. Its like the blue areas of the clutch are ultra-hard and rest of the plates jsut erode away, cutting down on friction area. I helped that blockhead tear that R90S 5 or 6 times in one summer trying to save money. In the end he burned up 2 new friction discs before he finally bought new clutch plates. That cheapass wasted alot of time and money. I am more frugal that most and I recycle all kinds of stuff, the clutch area is not one of those areas.
    #19
  20. phathead

    phathead jus a hair past noob

    Joined:
    Feb 26, 2008
    Oddometer:
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    Location:
    Fayettenam, AR
    those fab'd wind breakers are awesome!! Looks like something I would try, in a pinch...

    Great story and pics too! I've recently brought a '74 R75/6 back from the dead, and will likely spend more time on it than my '88 GS this season.

    Are you looking for replacement krausers?

    Cheers
    #20