Fellow Inmates, help a newbie get his bike running good, pleasssee.

Discussion in 'Airheads' started by Yachtie, Nov 1, 2012.

  1. Yachtie

    Yachtie Been here awhile

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    Aug 13, 2012
    Oddometer:
    105
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    Fuel vent wasn't it. Ran it without the cap and same thing. 20 minutes of good riding and then put put cough cough boom.
  2. Yachtie

    Yachtie Been here awhile

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    Where can I find the diaphragms?
  3. disston

    disston ShadeTreeExpert

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    [​IMG]

    It is part #11. They are large rubber things under the top cover of the carb. If you haven't had the top covers off yet be careful with it. Use a good proper fitting screwdriver. Anti-seize the screws when you put them back together. You may consider new screws if the ones you have are beginning to show their age. It is best to have the carbs off to take the tops off.

    Once you get the slides out hold them up to a strong light and stretch them. You are looking for holes in the rubber.

    I'm sorry but I don't think poor running after twenty mins is a symptom of diaphragim problems. Oh, and I don't know how well you will do from other sources but I found one that was almost $40 each.
  4. headtube

    headtube 6 mesas de invierno!

    Joined:
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    At your BMW Motorrad dealership. If you don't know about this, you should. It's a good resource. Make it your friend.

    Also this... Bing. I would suggest that you purchase the Bing carb rebuild DVD. A good investment. Seeing how things are done makes it sooo much easier. Also... grab yourself a workshop manual. Make it your bible. :D
  5. photomd

    photomd Been here awhile

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    Look at your carbs. The round, dome part on top holds the diaphragm. Undo the 4 screws SLOWLY. There is a spring under there that will push the top off. I usually hold the carb top down with one hand and remove the 4 screws with the other. Then slowly let the spring push the top up and remove it. Look at the diaphragm and how it fits in the carb body. The outer lip should seat in a grove and the diaphragm will have an indexing mark on one side that will fit in a corresponding grove. Make sure you see this, you'll need this info to reassemble correctly. Other than that, lift it out and take a look.
  6. disston

    disston ShadeTreeExpert

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    1976 bike. It originally didn't have the large spring under the diaphragm in the pic although riders do add this so it might be there. I have them in my carbs.
  7. ME 109

    ME 109 Long timer

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    You rode the bike and all was well for twenty minutes? Gotta be that new ignition.
    Not that I know what I'm talking about mind you.:1drink
  8. disston

    disston ShadeTreeExpert

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    Sometimes something just sounds right. ^^^^^^^^

    Electronics do break this way.

    BTW, Who told you anybody here knew what he was talking abut?
  9. Yachtie

    Yachtie Been here awhile

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    I think it's ignition too. Unfortunately I didn't install it and my ahole of a friend who did swears he did it right and refuses to even look it over. He took my money to install it though with out a problem. O well. I'm out of town the next week and am going to read over the ignition info and hopefully get it sorted upon my return.
  10. woodgrain

    woodgrain In-Dented Savant

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    I could have told you last week.

    Woodgrain
  11. disston

    disston ShadeTreeExpert

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    The friend of yours mechanic should at least be willing to look at it. But the symptom of not running well after 20 mins doesn't sound like it is an installation problem. It sounds like the electronics are breaking down inside the module after they get warm. There may be a test for the unit but it's usually something we can't do. So the module goes back to the seller who can at least compare it to a known good unit.

    One of the problems with after market ignitions, we don't have the expensive test gear. We would like to revert to the stock wiring as a test but in your case that would be difficult.

    I would contact the people who sell the unit. See if they will either give you a test or will do some tests themselves. They will probably help. The bike will be down while you don't have the module.
  12. ME 109

    ME 109 Long timer

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    That would be my next move. I also think that the 'right' salesperson would know how to remedy the situation, or advise whether the installation is incorrect, or whether a component sounds faulty.
  13. photomd

    photomd Been here awhile

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    As I said before, I'd test the things that can change as it gets warm. I'd test the carbs for leaks and the simple tests I listed to rule in/out the carbs, fuel supply and the coils. If those test OK, I'd switch back to the original ignition and see if it runs OK.

    Disston...it sure looks like it has a spring on top of the diaphragm, but I could be wrong.
  14. disston

    disston ShadeTreeExpert

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    Not in the picture I posted. That is the generic picture for many years but the spring shown in this picture has no number attached to it because it isn't a part for the /6es. My '75 R90/6 did not have springs. I have added them which is popular to do.

    I don't know what year was the first to get these springs but I do know there are two different versions. Apparently the first issue slide return springs were heavier than the second version. You have to figure this out or I could do it again but I'm tired of looking up parts tonight. The second issue springs, used until final production of Airheads are preferred over the earlier heavy ones.
  15. bmwhacker

    bmwhacker Still on 3 wheels

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    Fine example of a fully "shot" 32mm Bing diaphragm. This one failed while running down the road. I always carry a minimum of 2 spares...one for me and another for some other poor sot sitting along the road.
    Sometimes they'll get a small pinhole in them too. your symptoms sound like something else though...What? I'll be keen to find out....wish you were nearer to me...I love solving mysteries!

    [​IMG]
  16. Yachtie

    Yachtie Been here awhile

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    Got in touch with the ignition company. Have a few things to try when i get back into town. All symptoms are leading towards a wrongly installed ignition. Last time i'm letting friends work on my bike, well anything for that matter, been screwed over on my truck as well. If its something i can't do myself just going to pay a expert to do it right the first time...
  17. disston

    disston ShadeTreeExpert

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    That's a tough one. I used to work on my friends cars when I was younger. Maybe I did it different. I didn't have this problem tho. My friends said I was great. I saved them money or I sent them some place else. Sometimes I didn't save then money. It all seemed to work out but looking back on that now I must say I didn't always know what I was doing. With something like the installation of an after market ignition on an Airhead? They have directions. How can you not do it right?

    I guess you want to not use that friend for bike or other mechanics work but this doesn't mean he's not a friend I hope.
  18. photomd

    photomd Been here awhile

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    Yachtie, where are you?

    If you're near Florence, SC, I'll be glad to help when I have time.

    I think you'll learn a lot if you can hook up with some airheads in your area. That way you can learn some mechanical basics as well as some of the quirks of our bikes.
  19. bmwhacker

    bmwhacker Still on 3 wheels

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    I love points & condensors!!!!!:freaky
    to hell with the electronic gizmos!....:D
  20. Yachtie

    Yachtie Been here awhile

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    Aug 13, 2012
    Oddometer:
    105
    Location:
    Coral Springs, South Florida
    Well been out of town for the last 7 weeks. Back into town tomorrow and need to get this bike problem solved so I can enjoy my airhead! I don't even know where I left off.

    My first plan is to try and remove the new ignition and install the stock one. Problem I face is I didn't install the new one and it has a 41 page instruction manual. Anyone in south Florida willing lens a expert hand?