1984 GS1150ES #2 & 3 cylinder cutting out no spark

[Anonymous]

I have a 1984 GS 1150 ES that when I got it would intermittently loose spark to number 2and 3 cylinders. The ignition system had been modified to Dyna S pulsar coils wired directly into the harness going directly to the ignition coils also aftermarket. The black box had been eliminated. I was told that these coils were an inductance discharge system and did not need the capacitor discharge box. One of the ignition coils had a slight crack in the casing so I replaced them with Accel ingnition coils. All was well for about 2000 miles then the problem started to reoccur, again intermittently, then got progressively worse to the point that the cylinders will only fire sporadically, but for the most part not at all. The battery is brand new as is the voltage regulator as I replaced it with an aftermarket unit when the stock unit burned out 6 months after I replaced the ignition coils. The tach also does not function as I was told it reads off the 2 and 3 cylinders. I am about to replace the pulsar coils as they are the only componet that has not been replaced. Any ideas about anything else that may be the cause? All connections have been checked. Plug wires are new as they came with the coils. Any help would be greatly appreciated as I really like this bike. Thanks, MIKE IN MILWAUKEE.

[Doze]

Mike, I have a 84 1150es also that exhibited the same symptoms, but I took care of that by installing the Dyna S ignition and coils. It's run perfectly since then. Maybe you have a loose wire or bad ground somewhere. Sorry I can't be of more help.
Doze.

[arveejay]

I just had to replace a set of accell coils which were new. They worked fine for about 40 seconds then dropped off, 2+3 first then 1+4 10 seconds later. Stock coils are working fine.

[Dink]

If the tacho is fed of the 2\3 coli and is not working this should tel you that the coil is not getting power so go ahead and replace the pulsar coils but make certain you do a continuity test on the wiring feeding the coils.
Dink

[kz]

Intermittent faults are the hardest to find in my opinion.

As I understand the fault now appears so that you can measure "on the driveway".

In my opinion, then a fault appears; you should basically always ask yourself if something has happened in connection then the fault first appeared.

Many times things are related for example during normal maintenance you touched a wire making bad connection, hit some wire to ground and made small short and so on.

Always try the easy things first and try to isolate the problem.
Now there are different ways depending of your measurement equipment and skills.

Check all the basic things (as I read you already have).

But then I would try to isolate the fault, in this case disconnect the lead on the coil, to the tacho; to be sure that thread does not disturbed anything (tachos on the GS 1150 1984 can be tricky for sure :roll: ).

If unsuccessful I would check change the wires on the coils with each other and see if the fault go to cylinder 1 and 4 or if it still is at 2 and 3.

If it changes I go for the coil Ohm test, high Voltage cables or plugs.

If not you can try to "rewire" the low voltage lead by a separate new wire from the ignitor to the coil just for test.



This post is getting long...

But last, TO MEASURE IS TO KNOW.

If you can get the grip of an oscilloscope; this marvelous type of instrument can tell you a lot.

Most people think that oscilloscopes are very complicated, phase angles, time base, lots of channels and so on, in many applications tey are, but on the GS you really don't need a fancy type of oscilloscope, you only need to adjust about three knobs and look for a square signal.

Just connect the oscilloscope probe on the same lead as the tacho and see if you have a square signal that looks the same way as on the working coil. If yes, change the coil, if no make the same measurement at the ignitors output, if still no signal measure at the ignitors input from the pick-up coils.

Last..

Sometimes one fault creates a new one, i.e. you have a short in one circuit resulting in that an other part bakes down, if you change the part broken it will directly brake again.

Hope all this is of any help........ :roll:

[skip]

Had the same problem I think . Did the amount of frequencey between mishaps get more often as time went by? Mine was a bad coil It was a dyna. It started running on two every now and then , then more often. if i let the coil cool down it would run on four untill coil would heat up . Changed coil 5000 mile ago and havent had a problem since.......skip