Topic: ignition problem with cb750 with martek ignition

[pampadori]

this thing has been great since i've had it.  but last week it started only running on cyl 2 and 3. 
I have a martek ignition replacing the points.  1 and 4 get no spark.  if i swap the blue and yellow wires on the martek the symptoms change to cyl 2 and 3 without spark.  Now, to further complicate things if i depress the starter button on the right controls, cyl 1 and 4 will spark.  if i let up they stop.  sounds like a short or ground issue, but i don't know where to look. 

can anyone offer something to test or try?

Shaun

[City Boy]

Thats a weird one pampadori.I think you should go over all your lectric connectors.disconnect them ,clean ,check for breaks or bare wires while doing so.The fact that with starter depressed you get spark on all cylinders leads one to think components are all ok.Cardinal rule when troubleshooting lectrics;Order of probability is 1,connections,2,wires,3,components.This rule does not apply to products from Joe Lucas.

[nickjtc]

This rule does not apply to products from Joe Lucas.

The nickname of that company as 'The Prince of Darkness' was totally unfounded and their products have been unfairly maligned. 

[1080]

I ran a Martek electronic unit for many years and finally it was dropping 2&3 intermittently. I tried everything, new plugs, new plug wires & boots, re-did the wiring from the battery to the unit & to the coils, cleaned the grounding at the units mounting, but still the intermittent continued until it started to stay off longer. Finally I had the points cover off with the bike idling (was working on all four that time) & I hit the unit with the butt end of the screw driver & sure enough I could make drop 2 & 3, hit it again they would work. I re-checked the units grounds & the engine grounds, but that did not any differents. Your Martek maybe toast. Check everthing first or tap that Martek when running.

[754]

1080...
next time, check the mainjet holder FIRST

















>>>>>>>>>>> RUNNING  >>>>>>>>>>>>>>

[1080]

Lesson learned, DO NOT answer the phone when you are in the middle of cleaning your carbs especially if it's 754 on the phone asking if you are ready to go to Bonneville!

[754]

double-checking your work....

10 times quicker than a do-over................

[pampadori]

i figured it out.  had a short to another wire and when you hit the starter button, 12 volts to that wire is cancelled.  so it repaired and running strong! 

I tried the "tap" test like you mentioned.  got nowhere.  but after looking at it, i found how it worked to be very interesting.  looks like it uses a light signal to determine fire.  not magnetic like the other brands.  kinda cool. 
thanks for all the suggestions.

[City Boy]

Good show pompadori!!!Lectric ills can be very elusive and frustrating,you done good.   P.S.Can you detail what and where you found the trouble so I can commit it to my memory bank.I also have a Martek ,model 440 on my unit.I have the instructions that came with it,if I can help with info feel free to inquire.    Rock On

[SOHC4#1578]

Good show pompadori!!!Lectric ills can be very elusive and frustrating,you done good.   P.S.Can you detail what and where you found the trouble so I can commit it to my memory bank.I also have a Martek ,model 440 on my unit.I have the instructions that came with it,if I can help with info feel free to inquire.    Rock On

Just saw this post and also have a CB750 F 75 with Martek 440 iggy.
Could use a copy of the  instructions, please.

Email to blw@sympatico.ca.

Bob W.
SOHC4 #1578
CB750 F 75
CB650 C 80