got those airhead no start blues

Discussion in 'Airheads' started by newride, May 13, 2010.

  1. newride

    newride Been here awhile

    Joined:
    Aug 18, 2008
    Oddometer:
    706
    Location:
    San Fran
    So,
    She has been sitting since Nov 09 in the shed. Had lots of trouble starting her last fall. Starter should be fine. It got rebuilt only 4 years ago, and it was running good when I parked it.
    Pulled it apart to see if the starter connections were okay. I pulled the wires off the coils and put dielectric grease on all conections.
    Put it back together, new Westco battery. No start. It turns but never catches.
    The other symptom is gas comes dripping out of the right carb. I pulled off both float bowls to see if a float was stuck, nothing.
    Valves?
    I was told long ago by my mechanic and his assisstant that the valves close up more over the winter and you should do them in the spring. Sometimes I believe this and sometimes I don't. The valves were done along with the rings last fall.
    Argh, this bike is a pain sometimes. I just want to ride!
    I guess I should go back to the basics: fuel and fire.
    #1
  2. TimTowtdi

    TimTowtdi Been here awhile

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    Well, if the valves were recently done, it could be that they need adjustment as the gaskets settle in. They usually tighten up during the first 600 miles or break-in. Maybe you should check them. They wont usually tighten just sitting, but if you were having trouble last fall, and still this spring, it is a possibility.

    As for the leaking carb, maybe the float does not float, or maybe you have a speck of dirt in the float needle seat. Drop the bowl and turn on the fuel to allow some to flow out. Then try again. It could be out of adjustment.

    TT
    #2
  3. batoutoflahonda

    batoutoflahonda Long timer

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    Gas out of carb?

    Out of the bowl vent or boots?

    Was the starting issue because of a bad starter? Or was it turning last fall and not starting? Is it leaking gas while cranking or just when you turn the gas on?

    Reason being, if the bike ran fine last fall, and you took it apart to put dielectric on stuff, you may have pulled/pinched (choke or throttle) a cable putting it back together. If so, gas will wet the inside of the boots pretty heavily. If it's coming out the vent with out cranking, then odds are the float is hanging, or the float needle isn't seating.

    Most the time if bikes were running fine before being parked, it's crap in the carb. Or mice.
    #3
  4. danedg

    danedg Horizontally Opposed

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    Fuel, AIR and Spark.....
    I'd look for another mechanic....
    Change the plugs....
    #4
  5. newride

    newride Been here awhile

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    why would valves tighten when rings are done?
    Just curious
    #5
  6. newride

    newride Been here awhile

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    Aug 18, 2008
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    Plugs should be good. I change them every fall.
    My mechanic has been working on BMW's only for over 20 years, but he has been wrong before.
    #6
  7. newride

    newride Been here awhile

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    706
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    gas is coming out of bowl area and one of the rubber hoses that brings it to the carb. I feel like gas is backing up on the right side.
    #7
  8. dilandau

    dilandau Been here awhile

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    can of starter fluid is your friend in this situation. directly into the carbs- use fingers or throttle to move the body out of the way so you can get in there-

    if it fires right up, you know its fuel/air. if not, you know its compression or spark. if it does start--

    check your air by taking off your filter-- (which you did anyway with the starter fluid) - put your hand over the carb intake and feel if its pulling air- you might get a big splash of gas on your hand. this is good. if you dont get the splash, might not be getting good fuel to the carb - check float etc- clean all your jets. using your hand to give less and more air, you can sort of fake Choke the carb and it might start. this usually means your air filter is need of cleaning etc.

    if its not pulling air, then yeah, compression and valves or perhaps your choke is stuck on blocking the air etc.

    obviously check your plugs, ground them and try and start, see if they spark. I believe with bmws its not a good idea to try and start with the plug not grounded.. so make sure its well stuck to your block,

    clean and electrolube the inside of your plug caps. if they are metal like mine - water and electricity and any ph imbalance makes for quick corrosion sometimes.

    yeah, the list goes on. keep trying. i had a no start situation that pissed me off until i found the loose wire. and of course, it was a wire I had done. my own damn fault!
    #8
  9. newride

    newride Been here awhile

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    Thanks Dilandau,
    Yeah, stepping away from it right now is the best thing to do. :D
    #9
  10. MacRunch

    MacRunch Adventurer

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    Do you still have the original fuel lines? Ever had a carb rebuild with new o-rings? If you left the gas in the bike over the winter, the ethanol can eat up the rubber and get small pieces that can block the orifii in the carbs. Had to replace the fuel lines and rebuild the carbs on my '75 R90/6. If you have an air compressor blow out all the little holes. One common block point is in the float bowls. In one corner of the float bowl you will see a channel with a tiny hole at the bottom. You can either blow it out or maybe even use a fine wire (I use the E string from a guitar.)

    Good luck
    #10
  11. newride

    newride Been here awhile

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    good idea! I took all gas out of it over the winter, but I know the problems with ethanol. I will check it out though.
    #11
  12. tres

    tres Quixotic Adventurer

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    Did you check the float needle for wear when you checked the float? It would require actually pulling the float off & then checking to see if there's a groove around the end of the float needle.

    Also, I've pulled apart carbs and have been very surprised at the amount of dirt & other junk that they collect up in the jet chambers. So +1 for carb rebuild if you haven't done it yet.
    #12
  13. TimTowtdi

    TimTowtdi Been here awhile

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    Typically the head is pulled when the cylinders are pulled and a new head gasket is used. That new gasket will set in and the valves will tighten. If they reused the gasket, there will be less settling.
    #13
  14. bmwhacker

    bmwhacker Still on 3 wheels

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    Ignition condensor could be a suspect too...:confused ....my (freshly re ringed) BMW was getting spark but wouldn't fire....condensor was the culprit. (Proper) spark, compression, fuel and you're off.....
    #14
  15. Nialis

    Nialis Super Motarded

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    This is one of those times, pull a plug wire and verify spark, screwdriver is all you need ;) Even a terribly maladjusted carb and uber tight valves the engine should attempt to fire.

    Check the Coil and Hall Effect Sensor (if you haz electronic ignition, points of you don't) if you have no spark.
    #15
  16. Camel15

    Camel15 Adventurer

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    May 10, 2010
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    Here are some more basic steps prior to doing anything drastic:
    1) drain ALL the old fuel, tank, carb bowls everywhere you can and get fresh gas in it.
    2) with the float bowls off the carb turn on the fuel and see if it pours out. if it does clearly you have something stuck in one of the carbs...address that by flicking the float up and down wit you fingers and if gas still leaks by take it in for a carb rebuild.
    3) if gas is fresh and carbs floats ok. then pull a spark plug out, stick it back in the wire, lay the threads on the cylinder head and hit the start button. YOu should see a spark jumping across the plug. If so, then try the other side (put the first one back in before goign to the other side). if no spark then take it into the shop and have them trace the reason (short, wires, diode, coil...)
    let us know when it fires and waht the culprit was!
    #16
  17. newride

    newride Been here awhile

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    can't get to the bike till sunday. I am going to try all of these things. Sucks having a bike in New england sometimes, they just sit there over the winter. Got to ride them more!
    #17
  18. Grider Pirate

    Grider Pirate Long timer

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    Has anyone mentioned draining the tank and putting in FRESH FUEL? The gas today goes bad pretty fast. I'd put my money on a fuel/carb issue.
    BTW, when I know I'm not going to ride a bike for more than a month, I drain the fuel and put it in my car, and put a couple gallons of AVGAS in the bike, run it for a few minutes, and shut it down. I have no idea why, but AVGas is good for years.
    #18
  19. kbasa

    kbasa Roubaix! Super Moderator

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    Check airbox for mouse nest.

    Really.
    #19
  20. Jasper ST4

    Jasper ST4 Guest

    I was tinkering with mine after a long winter and some construction guys were working near the garage. I found a dead mouse in the box and made a big production out of pulling it out with tweezers and saying loudly "I'll be damn, so that was the problem!" They were in awe.
    #20