GS1000 bad miss when warm

[grumburg]

Just finished my 78 GS1000 project. Starts and runs great for about 10 minutes, then starts missing and spitting, eventually drops to 2 cylinders. ! and 4 exhaust pipes are cold. Replaced the coil with a used one, no better! Experts?

[grumburg]

PS-fire at the points, none at the plugs

[sedelen]

Lets see,
Cylinders 1 & 4 fire 180 degrees from cylinders 2 & 3.
You could swap around the inputs to the coils from 1 & 4 to 2 & 3 and 2 & 3 to 1 & 4. You'd also have to do the same thing with your plug wires and see if the problem transfers to cylinders 2 & 3.

[Crankthat]

If you are sure the coil is good and everything is hooked up in the right order the next place I would check is the wires and connectors from the points to the coils.
Look for any sign of heat like discolored/melting.
When a wire reaches a certain temp it will lose conductivity.
Look for any spark jumps at night in the dark.
If you are brave and do not have heart problems you can find it in the daylight by running your hand over wires (will be hot) or coils and plug wires (will feel the jolt)
When checking the regular wires by hand you will have best results directly after bike has heated enough to cause your misfire/nofire.

[harrymthree]

i had this problem with my 1980 gs1000e, 2 carb slide were stuck, has to clean the carbs out due to sticky fuel residue

[tatu]

Might be worth a look at the condensers next to the points. Again as suggested swap them over to the other points and see if the problem moves.