Starting

Discussion in 'Airheads' started by Beezer Josh, Jul 25, 2013.

  1. Warin

    Warin Retired

    Joined:
    Aug 30, 2012
    Oddometer:
    3,422
    Amal carbs .. ticklers .. = fuel on your hands/gloves after tickling .. and on the bike under the carb .. got to luv the brits... The Spanish though used them too .. old Montesa I had.

    ==========
    Full choke when cold. No throttle, may be a very little whisper as it catches.

    If it is that difficult I too would be checking for air leaks ... throttle spindle?
    #21
  2. 190e

    190e Long timer

    Joined:
    Feb 20, 2013
    Oddometer:
    1,295
    There were some differences in the Bing CV enricher operation over the years. Early ones like my 79 flat tops originally had only one fuel hole in the disc which explains why it's all or nothing in operation. I don't know when they changed but later models have several fuel holes of varying size to provide a progressive action.

    There was service bulletin S1300179 100R issued in Jan 79 for the R45/65's with flat top Bings. It describes modifying the disc by enlarging each of the 4 drilled recesses to 2.5mm and drilling a 0.6mm hole in the 4th position. The bulletin also states that spare parts are already modified and any carbs updated by the dealer will have a spot of red paint on the enricher housing.

    Next time I have the carbs of I'm going to give this a try.


    Ticklers if they could have left out the mess was a brilliantly simple automatic choke that provided enrichment that diminished as the fuel level fell. SU did it much better by lowering the needle jet to achieve the same result.
    #22
  3. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,374
    Location:
    Silver Spring, Md
    I don't think the part about "early" carbs having the one hole is a good way to say this. I have a 1975 R90/6, which is earlier, and it has 4 holes.

    Some of the /5 carbs were the worst.

    Serves me right for spouting off about my bike being such a great pleasure to start. I went out last night at Midnight for a soda and the bike wouldn't start right away...ugggh!:lol3
    #23
  4. Beezer Josh

    Beezer Josh Moto-Amish

    Joined:
    Jan 19, 2013
    Oddometer:
    1,525
    Location:
    15.6 miles from the U.S. Capitol
    Haha! Awesome Bill! I just checked on this thread and it made me laugh. I offered to help a friend move a deceased sister's house this weekend, so haven't had the opportunity to install the new spark plugs and ride.

    As for sucking in the gasket, it's not. I changed it out, had the same problems, and pulled it apart to verify it was in the correct location-no sucked in gasket. Anyone tried anaerobic gasket maker in this application? I've used it on oil pumps-where you definitely don't want globs clogging the lubrication system-with great success.

    On a different note, and one to which this thread has shifted, I love the extended ticklers on my old Amal carbs. My BSA starts up MUCH better in the cold (or any time for that matter) than the BMW and I don't get gasoline on my hands. The only downside is that the area just under the ticklers is gas stained...it comes off with a bit of carb cleaner though. However, I rebuilt that bike not for show, but to be ridden!
    #24
  5. 190e

    190e Long timer

    Joined:
    Feb 20, 2013
    Oddometer:
    1,295
    Good point I should have said some early carbs....

    Perhaps it was only flat tops that were deficient in enricher holes.

    So Bing knew how to engineer a progressive enricher in 75. I can't fathom why they went backwards in sophistication bewtween 75 and 79 and then needed a service bulletin to put it right.
    #25
  6. Plaka

    Plaka Brevis illi vita est

    Joined:
    Jun 19, 2010
    Oddometer:
    4,625
    Set valves again, engine stone cold, use Go/No-go gauges. Pay particular attention to the exhaust valves.
    #26
  7. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,374
    Location:
    Silver Spring, Md
    Have you noticed yet? That a lot of what goes on with building and tuning and making these things go is what is called "Bench Racing"? Most of us build everything in our minds before we build it for real. Sometimes this produces problems and the process starts over again.

    The Pros, Bings engineers, do the same thing. They make it work and modify it in their minds then build it for real. The only difference between them and us is that they get paid to do this. :lol3
    #27
  8. stucknarut

    stucknarut Uh oh...

    Joined:
    Dec 28, 2011
    Oddometer:
    171
    Location:
    East Bay CA
    Dunno if it's your issue; from the sounds of it I doubt it. But fwiw, on my /5 the PO had also installed one of the early Dyna models. I was having starting issues and getting a very weak spark and a double timing mark until I changed the timing plate. That fixed it for awhile until the plate quit working and stranded me, at which time I just went back to points. That fixed everything.

    Another fyi, the Dyna manual actually called for bending the tabs on the advance to retard the spread of the weights. So you might check yours to see.
    #28
  9. bmwrench

    bmwrench Long timer

    Joined:
    Nov 10, 2006
    Oddometer:
    3,539
    Make sure the choke discs are on the correct side and that they are oriented correctly. Also, make sure that the choke jet in the bowl is clear.
    #29