Magna v30, 1984 problem. Funky charging system

Discussion in 'Motorbike Technical Discussion' started by rake, Jul 22, 2005.

  1. rake

    rake Guest

    I have a technical question:
    I have a 84 magna and lately a problem with the charging system has
    come up.
    The bike starts right up, but when it gets hot it sounds like the
    battery is dying out. So i let it cool down a bit "say 20 mins" and
    then it starts right back up and sounds great, but unless i give it
    that time it sometimes doesn’t have the might to turn over. I just put
    a new battery thinking that would do it but that didn’t help. I bought
    a used voltage regulator and still the same problem. Is there anything
    else I should be looking at, maybe the stator ??
    Little lost with this one....
    rake, Jul 22, 2005
    1. Advertisements

  2. Have you done a charging voltage check across the battery terminals
    with the engine running? If you see the voltage rise from 12 volts to
    about 14.5 or 15.0 volts and then the voltage drops off sharply as the
    engine RPM increases above about 5000 RPM, and then the voltage picks
    up again and again and again every time you roll the throttle on and
    off, your charging systems is OK...

    If theres's no problem with the charging system or a weak battery, the
    engine is probably pre-igniting on the compression stroke. The spark
    plugs electrodes are so hot they are glowing red and acting like a glow
    plug in a model airplane engine. The gasoline vapors in the combustion
    chamber light off before the spark ever occurs. This makes the
    starter's job very hard.

    Are you sure you have the right heat range spark plugs in your engine?
    Spark plugs that are one heat range too hot will make the engine

    You may have cooling system problems, the radiator might be crudded up,
    the thermostat might not be opening completely, but, as long as you
    have enough coolant in the engine and it's all the way up to the normal
    in the expansion tank, I would recommend either running premium gas if
    you're using regular now, or I would recommend opening up the idle
    mixture screws about 1/2 or one full turn. That will cool down the
    engine more than you would expect.

    An engine will pre-ignite on lean idle mixture when you try to start
    it, so that's the reason for richening up the idle mixture.

    The idle mixture screws are probably still hidden under the EPA
    anti-tamper plugs. One my Suzukis, Yamaha, and Kawasaki, I drilled a
    pilot hole in the EPA plug, screwed a small sheet metal screw into the
    pilot hole, and then pulled the screw and plug out with a pair of
    pliers so I could adjust the idle mixture screws with a screwdriver.
    krusty kritter, Jul 22, 2005
    1. Advertisements

  3. rake

    rake Guest

    Oh yea,
    Thanks for the reply, turns out the starter was falty and was
    draining the battery. The tricky part was that it actually worked so
    that would be the last place i would have looked. The bike still gets
    plenty hot though, if it wasn’t for the fan it would cook and melt.
    Thank you again for sharing your knowledge, it was something I will
    copy and paste for a rainy day..
    rake, Jul 24, 2005
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.