81 C70 Passport, burning bulbs,

Discussion in 'General' started by JPA, Sep 19, 2018.

  1. JPA

    JPA New Member

    Sep 18, 2018
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    well it's finally happened.. after years and years of trouble free service the Passport has started blowing the headlight bulb and the tail bulb. in the tech field we ask, 'well what was the last thing you did on it' so I'll start there. the Scooter was sitting in my garage for about two years, i started it after several kicks and it ran great for several weeks when I noticed that the reserve fuel line was not flowing.. i took the line out and it was totally clogged, that lead to a thorough carb cleaning followed by a removal of the gas tank to remove all the rust from it.. there was quite a bit of rust in that thing. when i put the whole thing back together and went for a ride the front headlight burned out followed by the tail light (but not the break light) i changed the bulbs to the same result. the bike has a battery but it's very low and i've never used it. i always just use the kick starter. i again went though the wiring but every thing looks good. i've ordered a new battery and will be going through a thorough tear apart to try to find the problem. i could use any advise and or hints at what I should be concentrating. on. i did notice that the bike was running rather rough before it burns the bulbs.... thanks for your help.. oh all the turn signals and horn work as should.


    PS. how do you delete a thread on this forum? i posted this same message on the wrong section. whoops.
  3. racerx

    racerx Administrator
    Staff Member Administrator

    Jul 10, 2005
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    Not familiar with the electrical system on this model. If it doesn't need a battery to run, then it has magneto igntion. The next question is how the rest of the electrics are powered..."balanced" AC to the headlight + half-wave DC to the battery, or everything powered by the battery. Sounds more like the former, which is the same as the CT70. I'd break out the multimeter and check both voltage and current. If you have AC coming through the battery charging circuit, the rectifier is dying.
  4. Karl81

    Karl81 New Member

    Dec 8, 2018
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    I have two c70 passports. I have been working on them for 9 Years. I have Service manual and know a little.
    Is your rectifier bad? (voltage regular )
    I think so from what you are saying. Usually they melt or get crispy from getting fried. I can help if your not sure.
    Oh yea, no battery or a dead short battery will put all the voltage into lights blowing them like a bad rectifier. I keep a rectifier on hand. I get about four year/5000 miles out of one. Two or three year out of a battery. Four if your lucky.
    #3 Karl81, Dec 8, 2018
    Last edited: Dec 8, 2018

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