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Thread: 48 missing and popping

  1. #1
    Join Date
    Feb 2018
    Posts
    10

    Default 48 missing and popping

    I have a 48 fl missing and popping. I just don't know what else to check...I put a freshly rebuilt 74b on it,leak tested the intake,new aftermarket coil,new condenser, checked points,timing dead on, started easily, ran beautifully for about 30 mile then shut off a block from home.Both plugs black and sooty. Bike did restart but ran horribly checked for intake leak again with carb cleaner no change in engine speed so I don't think it developed a leak. Could that coil be bad already? As far as electrical , I can't keep a headlight bulb from burning out if that has anything to do with anything any ideas would be greatly appreciated. Battery is brand new from Harley and appears to be charging.

  2. #2
    Join Date
    Dec 2001
    Posts
    432

    Default

    Who's coil?
    DrSprocket

  3. #3
    Join Date
    Feb 2018
    Posts
    10

    Default

    Quote Originally Posted by RichO View Post
    Who's coil?
    Drag specialties

  4. #4
    Join Date
    Mar 2008
    Location
    New Jersey
    Posts
    80

    Default

    I rebuilt the M74 on my '64 a few years ago and I used the Drag rebuild kit. I did not use the float included. I had heard too many stories of float swelling. I used a Rubber Ducky and have had no problems. When coils fail, they often times cause the bike to stop dead. After say 20 minutes the coil cools and the bike will start again. I think I would first recheck the float and setting. Make sure everything is according to the book settings for the float. I think that the float is your issue.

  5. #5
    Join Date
    Feb 2018
    Posts
    10

    Default

    I checked the float several times set at 1/4" as level as I could get it. It almost sounded like it was firing on one cylinder I'm out of town till tomorrow maybe I'll see if it runs well again when I get home that would point to the coil...this thing has me at my wits end I thought it had to be spark because I carefully assembled the carb and checked everything. I did use a rubber ducky float. I started at 3 1/2 turns out on the idle needle and leaned from there. 2 turns on the high speed. #19 fixed jet new 1-5/16 venturi. Thanks for the replies, I wish I could find a quality original style coil.

  6. #6
    Join Date
    Apr 2010
    Posts
    1,116

    Default

    Firing on one is usually the repop coils or serious intake leak & yes they can go bad that fast

  7. #7
    Join Date
    Feb 2018
    Posts
    10

    Default

    Quote Originally Posted by duffeycycles View Post
    Firing on one is usually the repop coils or serious intake leak & yes they can go bad that fast
    I was kind of thinking that, I had an off idle stumble so I put the leak tester I made and used the soap when I put the carb on. Also when I got it started after it started acting up I sprayed carb cleaner around it and there was no change in engine speed. It ran flawlessly for about 30 miles or so and shut off 1 block from the house! I have one of those round Japanese coils somewhere I'll have to try that maybe go over the wiring thanks

  8. #8
    Join Date
    Jun 2001
    Location
    Central Illinois, USA
    Posts
    4,308

    Default

    Quote Originally Posted by 65flh View Post
    ...so I put the leak tester I made and used the soap when I put the carb on....
    Bubble-testing is performed with the carb off, 65FLH!

    Never does only one thing go wrong at a time...

    ....Cotten
    AMCA #776
    Dumpster Diver's Motto: Seek,... and Ye Shall Find!

  9. #9

    Default

    Always check easiest theory first. Plugs, plug wires, coil, in that order. I once had a bike did the same thing and found the ground wire exiting the timer was shorting where it exits.

  10. #10
    Join Date
    Feb 2018
    Posts
    10

    Default

    Quote Originally Posted by T. Cotten View Post
    Bubble-testing is performed with the carb off, 65FLH!

    Never does only one thing go wrong at a time...

    ....Cotten
    of course, I followed instructions from your posts I couldn't believe how well it ran till it crapped out at the end of the ride. Unfortunately it has an o ring conversion. The conversion nipples do not appear to be leaking. I am considering having it converted back to plumbers and some of your peek seals made for it eventually

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