lost my spark

[chris p.]

about a muonth ago i started motor work on my 76 125 ktm motor. it was lacking compression but had great spark.so i pulled the motor washed it up,put in new top end parts gaskets ect.then i gave it a coat of paint . yesterday i cleaned up all the mounting areas for the bolts and coil. gave them a coat of electrical tune up grease and slid everything back togather now i have very little or no spark.what did i do wrong?

 

[Don Roth]

Chris,
Just a SWAG, but I would double check your
ground, an alligator clipped jumper wire
between your coil and motor should confirm
or reject this fairly quick. My reasoning may
be off, but the problem seems to have surfaced after engine removal.
-don

 

[TGTech]

If this engine has a Motoplat ignition, then I have some words of advice. Most of the Motoplat ignitions, are what are called "frame ground systems". This means that the frame parts of the ignition components, carry the ground current. The mount of the coil, the stator mounting points and all other mounting pieces as well. If there are rust and or corrosion in the mounting system, it can hamper the operation of the ignition. If this condition exists long enough, it can kill the ignition.

Everybody thinks about the coil to frame connection and the stator to the engine or adapter plate, but there are other paths that can cause problems. The engine to frame connection is one in particular, that I have had personal experience with .

Another, is the spark plug to stator ground: plug to head, head to base studs, base studs to cases, cases to adapter plates, and adapter plates to stator frame. If there is sufficient rust and or corrosion, this can prevent the engine from running. Trust me, I've seen it all in our business.

Dane

 

[Russ B]

I've got two possibles.
1. coil damamge by kicking it over without a ground path through spark plug wire (no spark plug, or plug not grounded when it was unscrewed) I remember reading somewhere the motoplat coils will arc internally and be damamged if the spark plug lead isn't grounded. If you have a known good coil, try it as a substuitute.

2. Same as everyone else. Bad ground path between stator and coil. You can try running a dedicated wire from a stator bolt to the coil mount. This gives a direct ground path without requiring the frame and engine to complete the circuit.