Lights "kill" engine???

[Nomad]

I had my lights running off the white wire and all was well, but recently when I connect the lights while the eng is running it kills the eng immediately. I don't have a "switch" for the lights just a "plug in" when needed. I checked the wires and the bulbs all is ok... this is puzzling, anyone have any input as to what the problem could be?....
thanks.
Bob

 

[jburr36]

How's the spark plug look?

 

[jburr36]

Maybe the light's resistance is changing with the temperature?

 

[jburr36]

Perhaps some moisture or dirt causing a short in the plug?

 

[Nomad]

Last time I looked it was a nice dark chocolate brown, the engine runs ok otherwise, it does seem to "miss" when I crack the throttle but it's always done that and I think that's because of the crappy mufflers the kits come with..

 

[Nomad]

I'll check the plug soon as she cools off... thanks for the advice.....

 

[FileStyle]

try the sparkplug wire! replace with a new 7mm wire. you can get a single wire from your favorite auto parts store. mine would do that also , I would have my bike warmed up good and as soon as I would try the light it instantly killed the motor. I replaced the wire and taa daa it works now.

 

[Nomad]

Plug looks good, I did replace the original plug wire when I built the bike.. But I'll take your advice Filestyle1 and replace the plug wire. I bought a plug wire kit for a 4 cyl chevy which gave me 8 plug connectors and lots of wire. The parts that connect to the coils also connect to the plug... 10 bucks, they wanted 8 dollars for one wire and connector....thanks for the tip;..

 

[Nomad]

New plug wire had no effect, still dies... Maybe I fried the white wire thingy inside, eng runs really good though....

 

[drhofferber]

is the light 12 or 6 volt...12 will kill the engine...dennis

 

[Norman]

your plug may look good but I'd say its toast if your killing the engine when you turn on the lights I've bee there. You can even clean the plug and it may work for a little while but soon it will kill the engine. You can be running along with the light on and the thing dies lights still work until the engine stops turn off the lights and the bike will fire right up but don't turn on the lights as they will kill the engine.
Time to change the plug. Plug wire is most likely fine.

 

[TexasDav]

Norman
I have a question about the voltage on the white wire. Is it 6 volt AC or 6 volts DC. I tryed my multitester and the thing went crazy, probly a bad multitester. The reason I want to know is , I had to put a rectifier on my honda NC 50 scooter because it put out an AC current.

 

[Nomad]

6 volt lights from an old Schwinn that was connected originally to a tire driven dynamo... the lights did work fine then all of a sudden, ..... bupkus..(nuttin)...

 

[Nomad]

your plug may look good but I'd say its toast if your killing the engine when you turn on the lights I've bee there. You can even clean the plug and it may work for a little while but soon it will kill the engine. You can be running along with the light on and the thing dies lights still work until the engine stops turn off the lights and the bike will fire right up but don't turn on the lights as they will kill the engine.
Time to change the plug. Plug wire is most likely fine.

Thanks for the tip Norman, it's a fairly fresh NGK B5HS... I'll replace it tomorrow and see what happens..

 

[Nomad]

How does the plug run the engine fine but messes with the light?... what is the "mechanism" that causes this? is a plug either bad? or good?.. is there an in-between?..
thanks..

 

[Finfan]

The output of your magneto might be dropping off. If you have a spare one laying around try swapping it out and see if that solves the problem. I guess the CDI could also be a problem. Either way the increase draw from the lamp is killing your spark so it must be one of the two.

 

[Nomad]

The output of your magneto might be dropping off. If you have a spare one laying around try swapping it out and see if that solves the problem. I guess the CDI could also be a problem. Either way the increase draw from the lamp is killing your spark so it must be one of the two.

Thanks for tip, I hadn't thought of the increased "draw" that could cause the "kill".. but that makes alot of sense. I'll give 'em a try.. I have an engine still in the box unused...

 

[tyrslider]

Two strokes have a way of ruining plugs. they'll look fine but stop working. If it's on it's way out then there'll be more resistance and the path of least resistance will be the lights. B5 is too hot, it's B7HS you want or a 6 if your fouling the 7.

 

[Nomad]

Thanks tyrslider, I used the 5 on a previous recommendation from this site, anyway, the plug's "read" looks good it's a dark to medium brown, if it was too hot would it be too "light" like the color of coffee with cream?..or can the plug be too hot and look "proper" to the 2 stroke?

 

[FileStyle]

I had changed the type of plug, the magneto, the bulb and still no luck until I changed the wire! good luck nomad ,hope you catch the gremlin