My atv has a very weak spark. Once in a while I can get it to fire but it doesn't last. Grounding the plug to the block shows a spark but it is barely visible. I have tried 2 different coils, both that speced out good, new cdi, and a new pulse coil. All of the electrical specs out good, kill switch is operating as it is supposed to, neutral light is on, plug cap ohmed out good, I snipped the wire a little bit for a better connection. Don't know what else to check. Battery is good and has a full charge. Grounds are good tight and clean.

 

The spark on those old 200s is not that bright. I found that adjusting the pulse coil to the minimum air gap, gave the best spark.

 

Well, if they typically aren't very strong I must be on the right track then. Spark seems to be consistent now, just not strong. Well, guess I don't know what is wrong then. 130- 140lbs compression, spark, adjusted valves, rebuilt carb, and no go. wont even sputter with a shot of starting fluid.

 

The 86 doesn`t have a fuse does it? Otherwise that may be your issue, I own two but they`re tucked away.

 

It does have a fuse, but I have checked that. I did get it to start for about 15 seconds a couple times. Pulled the plug and there was no spark. Seems like it will spark for about 10 to 15 seconds and then fade out to nothing. This is still on a cold engine and using any number of combinations of cdi's, coils, caps, and plugs.

 

Could the voltage regulator have anything to do with it? It is about the only electrical component I haven't replaced. Where does everything ground to? I have a main ground from the battery to the starter, but don't see any other grounds other than the green wire into the stator housing which I believe is a ground

 

How about the the magnets on the rotor/flywheel. Still feel good and strong? Have heard of some weakening or losing magnetism altogether. Excess heat and impact (dropping on the floor) is bad for magnets.

Agree with merryman, many engines are built with too much air gap at the pickup coil. My street bike is one. The mod for it is to slot the bolt holes so it can be set to around a .012" gap. Helps more with hot starts on mine though.