intermitent no spark left cylinder

tanman2003

i checking the timing and the timing light hooled up to the left cylinder does not flash when it runs crappy. then it will start to fire and it will run good.

what would cause it to start and stop fireing?
right side is going good.

thanks for any help.

i have the timing parks set right.

grizld1

Check the leads from the points to the coil, the coil ground, condenser ground and contacts, plug lead contact at coil and plug boot end, plug boot itself, plug wire itself, and the coil itself. 650 Central has a nice set of procedures and specs listed. I'd suspect a loose contact somewhere.

tanman2003

checked the red and white wire it has battery voltage, checked wire at coil which is brown in my case and it has battery voltage. is it normal for a coil to get hot? it seems that my left coil gets hotter than the right one which was warm, could be that i had the ignition on when it was charging that coil.

the other wire on the coil which is orange in my case had continuity with the wires on the points.

are the coils interchangeable, maybe i can swap them side to side and see if the left one sparks good and the right one dosent.

tanman2003

where is the coil ground? i only have three wires on my coil brown, orange, and the hight tension wire.

things are kinda wierd on it since it is retrofitted.

where is the condenser ground ?

grizld1

Try checking impedance on the hot coil--see the 650 Central site for procedure. You'll find the condenser and its leads mounted to the head stay. It should be easy to see if you take the tank off.

tanman2003

how do u test the capacitors, i tried charging them up but they do not spark. i hooked up + to the yellow or blue wire and - to the ground wire. i held it there for a few seconds and then touched blue or yellow to the ground wire and nothing.

grizld1

I just swap 'em out to check.

tanman2003

ok
ill buy some but i just wish there was a way i could know now, i have to order them.

grizld1

Just make sure the connections are tight and eliminate other possibilities before you buy parts on a guess. Have you tried putting a meter to the coils or swapping coil connections to see if the problem moves to the other cylinder?

tanman2003

so i just threw some parts at it, new coils and a capacitor, 41.00 from mikesxs and it runs great now, thanks everyone for the help.

i diddnt just sthrow them at it, it was an educated guess on parts that are not easily testable, but all the connections look ok,

but it seems like i might have a short somewhere behind the headlight, cause i blew 2 fuses (after replacing the first one the second one blew, so i tugged on the wireing harness and since then it has not blown,

gotta check behind the headlight, i think the previouse owner did a hack job on the wiring because he converted it to points and had some wires left over. i think it was a special because its an 81 with the vin starting as 4M4.......

so we'll have to see, but its running great.

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