[SDRED]

Hi there, my 93 900SS Starts no problem has spark on both cylinders until I rev it up front cylinder spark disappears, am using an inline spark tester and rear cylinder sparks great, also used an infra red thermometer to determine the front cylinder is not working. I have read other threads on this subject so I have done the following:
Swapped igniters, tried two different coils, changed plug, changed plug lead, checked pick up resistance both 106 ohms.
I am out of ideas and would really appreciate some info/help that would solve my problem.
Thanks, Steve

 

[belter]

i have seen pick ups do that. or sometimes they'll start on one and pick up the second with rpm. check the ac voltage coming out of the pick up.

 

[ducvet]

It could be the pick up coil under the left cover. I have seen a bike where when it warmed up the engine grew just enough the flywheel touched the pickup wire and broke contact. After it cooled back down the clearance returned and it worked again.

 

[SDRED]

Tomorrow I plan to remove the left cover and check the pick up gaps they should be 0.027" I think

 

[ducvet]

Before taking it apart I would ohm test the pick ups both cold and hot to see if they are breaking down. Then when you are in there check gap and inspect wires. could be nothing more than a pad pick up as well I lost one on my 750 monster much the same way once.

 

[SDRED]

Problem solved. On the horizontal cylinder igniter there are two plugs a 2 pin and a 3 pin. The 2 pin comes from the pickup with a white wire and a red wire. I had these wires reversed in the plug. I purchased this bike disassembled and to get the pickup/igniter wires thru the nut gland in the left engine case I had to remove and refit the plug. The workshop manual shows a clear diagram of these connections and I simply reversed them. Runs like a champ!

 

[SDRED]

Of course many thanks to those that contributed to this thread

 

[Rex Coil 7]

Yay!!!!! :grin2: :smile2:

Click on the image to celebrate.

 

[belter]

i didn't recall that as a symptom of reversed wires, but i haven't had that for a long time on a kokusan. i've had it with bosch pantahs recently - there the cylinder will run at full advance all the time if the wires are reversed.

good find. certainly easier than pulling shit apart again.