Engine ONLY RUNS if white wire is grounded to frame!?!

[nidyanazo]

Craziest thing going on with this HT motor..

Customer said it rode fine for a few miles then shut off.
Brought it back to me and I took a look. At first I pulled the plug and cranked the engine to see if it was sparking.
Was not. I removed the kill switch from the equation, and had now only the blue and black from the engine to the ign box connected.

The white wire was just dangling.

Tried to start it, and it would not fire.
Swapped the plug, ign box, magneto, checked everything over and tried again. It fired up but ran slightly poor... I pulled over with it idling, and looked down. . . The white wire was grounding out on the frame! I could even see the sparks quite clearly. So I removed it and the engine died.

Went to start it again, nope wont start.
I put the white wire back on the frame and presto it starts right up.
What's going on here?

Cliff's: Engine ONLY runs (and poorly) with the white wire fron the engine grounding out on the frame.

What's to make of this?

 

[Creative Engineering]

nidyanazo,

You either have a bad coil, or the black wire has a break in it.

The coil is actually 2 coils wound on the same frame and connected in series. One over the top of the other.

Coil 1) 300 turns of 26GA., (inner coil), connected to the White wire. Opposite end...soldered to the coil frame.

Coill 2) 3,600 turns of 35 GA., (outer coil), connected to the blue wire. Opposite end...soldered to the coil frame.

Black wire to the coil frame.

Jim

 

[killercanuck]

Wow that is crazy Nidy, do you have another mag around to test on it? What Jim says makes sense, if the black wire is broken somewhere the white would complete the circuit. Only it would complete the crappy 300 turn, and not the 3,600.

Dang, that's the first time I heard of that happening. Keep us posted.

gl. Greg.

 

[Maxvision]

...the signpost up ahead...your next stop...The Twilight Zone!

 

[DudeZXT]

Definitely an issue with your engine electrical system not grounded properly with the bike frame and most likely in the magneto connection to the engine casing.

 

[nidyanazo]

Definitely an issue with your engine electrical system not grounded properly with the bike frame and most likely in the magneto connection to the engine casing.

Ended up being the magneto was bad, as Jim said. I had replaced it with another one that turned out to be bad also, so that was confusing lol

Thanks!

 

[Creative Engineering]

Ended up being the magneto was bad, as Jim said. I had replaced it with another one that turned out to be bad also, so that was confusing lol

Thanks!

Manufacturing defects are the worst!

I had a new customer bring a bike in a few months ago. The coil was bad...it was the first time I had seen this. The coil checked good with a VOM, no dead short in either winding of the coil...normal ohm readings! I put on a spare that I had here at the shop and the engine fired right up.

The customer told me a few days later that his engine was running better than it ever had...strange!

Hong Kong Phooey strikes again...

Jim

 

[bairdco]

is it possible that the wires are soldered to the wrong sides on the mag?