Back on an Airhead - 1975 BMW R90/6

Discussion in 'Airheads' started by tete, Aug 27, 2012.

  1. tete

    tete clown shoes

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    ok Ill get on this. Worst case scenario I'll ride it here and there till summer where I can save money. In the mean time I believe I can afford the gauge by next paycheck. The Oil I will I will get on right away.


    Thanks
    T
  2. disston

    disston ShadeTreeExpert

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    Using 20w-50 oil will help a lot. It is what you are supposed to be using.
  3. tete

    tete clown shoes

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    Ok for starters I had the wrong oil. I finally got the right stuff replaced the oil pan gasket and new filter and oil.

    Also modified to have the crankcase spit into a can outside the carb here are the pics. Some won't like that I cut a little but I found no other way around as the bend was too tight. Next up replace the turkey valve with proper Reed type.
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    Ill post better pics when totally done.
    The hose coming out of the crank vent is kinda ugly and will only get uglier till I find a Bette looking solution. But having a clear one will let me know how much is kicking out and when.
  4. tete

    tete clown shoes

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    Took her out for a decent ride today. Saw no signs of smoke from the right side or leaks coming from the pan. Still have push rod leak but at this point that is expected. Till I rebuild over the summer.

    The crank case vent is just dumping to open air until I set my can up. I put the proper bmw oil in there this time.

    Rides smooth
  5. Kt-88

    Kt-88 I like everything.

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    Awesome. Springtime. Ride time.
  6. MaraBiker

    MaraBiker Vozi Miško!

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  7. tete

    tete clown shoes

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    The problem w the way mine is set up is the stock air filter element is in the way and there is not enough room to bend and not crimp the hose. The way I set it up was the best way for me not to restrict / oil airflow. I hope to make it look cleaner. I do like the canister he made. Really clean idea which I will totally rip off. Lol.
  8. MaraBiker

    MaraBiker Vozi Miško!

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    Maybe you're right. I still have to get my hands dirty to see what can be done.
    Canister is a must do :lol3
  9. Plaka

    Plaka Brevis illi vita est

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    There is a real clean way to bring the breather hose out but if you already hacked a hole in the cover...well..a bit late. I sleep on my ideas for a week or two (or more) before doing anything I can't reverse.

    if you haven't changed the fork oil by now you are going to get to learn about rebuilding forks. must be changed yearly. Ditto the brake fluid. Do all the basic maintenance before spending on stylin' it up.

    Peel up the rubber on the top of the Konis and see what the dial is set to. (you did install them with the dial out, right?) You can increase the setting to make up for wear up to a point. BTW, AFAIK, they were never stock on any BMW. Factory used Boges, which didn't last long, or Nivomat self adjusters about which I haven't heard great reviews. Konis were the way to go back in the day. You can fit the OEM aluminum covers to them with a bit of filing and a spring compressor (to get the top eye off)

    Try gloss black enamel (with an artist brush) on the rusty spot on top of the carbs.
  10. tete

    tete clown shoes

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    No concern w the hack job on the cover. However please let me know if you have a smoother way to run the hose. I have it running from my outlet to a old prince Alberta cigar can. Either way more blue smoke from right carb.

    Thanks for the advice on the konis and such. I don't have the liberty of changing everything at once. All the "looks" stuff was either free dollars or very cheap.

    Thanks for all the advice and will hear you out on all that I can. I will look at the koni dials. As well as the front shocks but to be honest that will have to wait. I have a bud who is parting out a bike w dual disk up front. I'm trying to get that coming my way.

    As always adv has great advice. Thanks again.

    Sent from iPhone.
  11. Plaka

    Plaka Brevis illi vita est

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    But the breather back to stock and see about the smoke. But you got something worn in any event, I'm betting a valve guide. Look inside the rocker cover at the build uo, look through the spark plug hole with the valve open to see the valve lip and do a wet and dry compression check.

    Pistons move in and out at the same time. When they are moving in one side is on the power stroke, the other on the intake. As they move down they compress the air in the crankcase. But at the same time the piston on the intake stroke is sucking on the intake manifold. so the crankcase is higher than atmospheric pressure and the intake is lower than atmospheric pressure. The crankcase pressure gets sucked into the intake. A reed valve (poppet on earlier and should be changed) keeps the flow from going the other way and lets the crankcase get negative on the piston up stroke. You use the intake vacuum assist in preventing power robbing (and oil blowing) pressure from building in the crank case. Vent to the atmosphere and you lose this boost (and some top end lubrication). Now the engine pumps first against the reed valve and then only has atmospheric pressure to vent to (rather than a low pressure intake). Go to the atmosphere and you want the vents really big and any hoses really short and any filters really free flowing.

    Or you could not do it and say you did..





    Free and very cheap is always good.


    You do the hose with a bulkhead fitting. Probably make one in this case. But you drill a clean hole for your fitting. Hose attaches to barbs inside and outside the fitting. very clean and you can point that barb any way you want so the hose lays flat and clean to the case. I'm working on one, I'll shoot you a pic when it's farther along.
  12. tete

    tete clown shoes

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    Sweet. Look forward to seeing your result. I actually thought it my be something w the valves as well. I talk to a machine shop guy recently about my bike and he said the same thing. He said I could ride if like this and no real trouble. I plan on rebuilding over the summer. In which I hope to address alot of these issues.
  13. tete

    tete clown shoes

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    This is how mine currently looks. Certainly not winning any "show" awards.
    [​IMG]
  14. JonnyCash

    JonnyCash turd polisher

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    ^Nice! I love to see evidence that not everyone take this stuff too seriously.
  15. Plaka

    Plaka Brevis illi vita est

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    "mommy, why's that mans' motorcycle on fire?"

    "It's some just smoke, honey".

    :rofl:rofl
  16. disston

    disston ShadeTreeExpert

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    I like the way Tete has plumed this. Also gets the hose out of the intake runner.
  17. tete

    tete clown shoes

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    I'll take this as a compliment. :D

    I mean, i'm from panama, I've seen some pretty shady stuff that has a bike rollin for years. I'm never going to have a trailer queen or the perfect bike.. If it passes emissions, and gets me to work, alive. then Im cool with it. My bike aint pretty, not the fastest. But currently it's not blowing out blue smoke, dripping oil from underneath, and starts and stops when I need it to. Im not sure in my current condition I could ask for more. :1drink

    With the help from alot of people here Im pretty happy to be where I am at with it.
  18. JonnyCash

    JonnyCash turd polisher

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    I meant for you to take it that way.
  19. SERE Nate

    SERE Nate Been here awhile

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    I've really learned a lot from this build! great info
  20. tete

    tete clown shoes

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    Well thanks man even tho this summer the real fun starts. Rebuild etc. stay tuned. Certainly I literally know nothing about these bikes. So I'm learning from the guys. I also don't believe it always has to be perfect or expensive. Some times close enough is going to have to good enough. I'm on the road rolling and passing emissions. Two things that at one point seemed impossible. There are guys on this forum that have done everything except literally turn my wrenches for me. Pretty awesome. I'll never see these guys or be able to pay them back but they still do it for me and others. Pretty darn cool.