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View Full Version : 1978 ATC90 no spark



Russell 350X
04-20-2008, 01:58 AM
Tried 2 different plugs, cleaned up the AC generator because it was all nasty and rusty, has a good magnetic pull. No broken wires than I can see. Could I have a bad ground, if so what color is the wire so I can trace it? I'm not good will electrical, so help me out here guys, thanks;)

bigreddaddy
04-20-2008, 04:23 AM
I think the easiest way would be to use a volt/ohm meter, but first check your ground wire where it connects to the frame. Take it off and clean up the metal contacts real good with a knife or file, including where it contacts the frame.
Using the meter, put the -neg probe on a good spot on the frame and use the +pos probe to check each wire coming out right by the pull starter. Its a lot easier if you get someone to pull on the starter while your holding the probes. You should see around12v (or 6v) on the hot wire. If you have voltage there then just work your way down the electrical system, connectors, coil, plug wire, etc.

Mosh
04-20-2008, 09:50 AM
Mine was all hosed with no spark when I got it.
2 things I found.

Mice had made a nest in the frame and chewed up the wire harness.Check that as the coil is mounted in the frame under the seat.

I also had bad points under the cover in the head.
Fixed the wires,replced the points cleaned the carb and ran great.

p0ng
05-05-2008, 02:44 PM
i recently got a 1977 act 90 that i am currently working on (got it last week, been in a bar for at least the last 20 years). i've got i running but i had a no spark problem as well when i started. i don't know if you have the same problem i had, you seem experienced with hondas and all. i sortof hate to admit it, but for me, it was a matter of turning the right switch on. feel free to laugh... apparently the switch on the handle bar is refered to as the "emergency switch" and the "main switch" is the one on the front light. i had to set the main switch from the "O" position to the "I" position, as well as turning switch on the handle bars to the "on" position. since i'm really new to hondas (not to mention anything smaller than a tractor), i did not know this and spent several hours testing the various components before concluding there to be a ground in the wiring harness somewhere and which point i searched for a wiring diagram and found this forum site (http://www.3wheelerworldforums.com/showthread.php?t=56218) and once i looked at the wiring diagram, i realized my mistake and proceded to kick myself..... numerous times. like i said, i don't know if this is your problem, i doubt it really, but i would rather post and look stupid than for someone else to be making the same mistake i did and spend money only to find out later. good luck with your problem.

WaimakRydah
05-06-2008, 04:59 AM
Mine was all hosed with no spark when I got it.
2 things I found.

Mice had made a nest in the frame and chewed up the wire harness.Check that as the coil is mounted in the frame under the seat.

I also had bad points under the cover in the head.
Fixed the wires,replced the points cleaned the carb and ran great.

bloody mice u should have killed them for that