how to test for spark

[kevxs]

hey guys, i've been searching the posts for 40mins and can't find my answer . . .

will i damage anything by pulling a plug, leaning it against the block and cranking the motor to test for spark? I have always done this but I though I read a while ago that you shouldn't for some reason, can't remember or find why. I've just installed new coils, wires and plugs but it wont fire up from its winter slumber, (although i am getting a few fires), need to do some testing . . . . any advice?

thanks

[Yard Dogg]

Thats how I check mine, can't tell you if it's right or not, but so far so good. You could always put your tongue on it.

[Larrym]

Tesla's Light Show

kevxs,

Laying the plug against the head or any convenient place doesn't guarantee a sound connection and path for the spark to follow after it jumps the gap. It's a 50/50 (hit or miss) chance and so what you see with the naked eyes may sometimes be misleading.

The high voltage discharge of the coil tries every avenue to make it to the ground and if the plug body doesn't provide a good enough route then the electrons will try to find another path. This is usually at any and every weak point in the insulation of the wire or any conveniently close exposed connection. (20,000 volts will jump across 1 inch of gap in ordinary air...) Once the electrons break through even once, they'll never forget where this happened and continue to arc along the small carbon path the first electron left behind. Like the story of the little boy with his finger plugging the dyke, the hole will get bigger and bigger over time.

My solution to this is to not pull the plug at all. I simply put a known good plug in the wire/cap and then connect a jumper between it and the head somewhere. The jumper wire has little alligator clips at each end similar in size to (ahem...) "Roach Clips". This method ensures a solid path for the spark to discharge along with keeping the spark plug hole closed so no fuel/air mixture can puff out and be ignited accidentally.

I don't test just one plug at a time either. I put known good plugs in the ends of all the caps, connect the 4 jumper wires, and then put on a light show.

I also carry these jumper wires and plugs in my road kit.

[DGXSER]

Ive tested mine exactly as you described, pull one plug, lay it on the head so the bolt head section is touching/laying on the head, and turn the engine over. Look for a good solid blue spark to jump.

Talls me I'm getting spark to it anyway.

Have you made certain you got the wires to your coils correct? More than a few times folks have messed with the coils and then put the wrong wire to the wrong coil. Meaning, the grey wire and the ornage wire get crossed. Try switching those wires and see what happens.

[kevxs]

got er fired up but its smoking

hey guys, had my plug wires on the wrong plugs, my own stupidity, anyway got er runnin for a min but there is lots of white smoke coming out of the left pipe, is this just cause its been sitting all winter? i'm going to replace the fuse panel and do a few more things before i take it for a ride, i'm hoping it'll clean itself out once i ride it.

[DGXSER]

Could be, but do not take it on a long ride if it does not stop. White smoke also can indicate a lean condition IIRC, which can burn up the cylinders, so you will want to check your fuel mixture.

[Ken Talbot]

lots of white smoke coming out of the left pipe, is this just cause its been sitting all winter?

Could be, unless it is time for a new Pope...

[Larrym]

Could be, unless it is time for a new Pope...

Wait for it....

?

Oh!! The best ones have that "turbo lag": takes a moment for the boost to kick in but when it does....