94 cbr f2 ignition problem
 

I've random and weak/at times no spark spark across all four plugs causing the bike not to start. I've tested everything changed the plugs, the coils are in good condition and both pass the manuals tests, all the safety switches work and the bike was running so I know timing compression and fuel are all good just the spark is bad.

I did the I'm test on page 16-6 and everything was good other than the ignition primary coil... Seems strait forward so first I tried to change the plugs that connect the coils mini harness to the main harness I used weather pack plugs so I know there was a clean good connection but that did not solve the problem. I also cleaned the connection between the mini harness and the coils them selves which are relatively new and the connection points are clear and solid.

Am I getting to the point where the harness has too much resistance and I need to rewire? With that said no big deal the bike has been through a lot it my concern is what do I do about icm plug?? What type of connectors does it use? I haven't found any information on this and I would hate to start and get stuck on wiring the icm. I can pull the original wires out but then I will need new connectors that match original to use the original plug for the icm.

Is there any other way around this other than buying a used harness and hoping for the best?

Thanks for the help

Hi , got to remember the negative side of the circuit which is just important and sometimes more important than the positive side, check all your connections to earth as you need that good return to the battery, stator and rec/reg test will come in handy:)

Thanks for the response, I have tested grounds but I wil go out and triple check no harm no foul. As far as reg goes it relatively new and I know it's working fine and the stator is putting out a strong charge (bike ran all be it rough but it was running recently until the spark problem, and both stator and reg have been tested and are working fine), but if I have a full charge from a battery tender and go to start (battery is good) I should still be able to start/ at the least get spark right? If the reg or the stator is bad wouldn't it just die once the battery loses power and no longer has enough juice to produce spark? (Once went a few miles and made it home withinout my reg when it was knocked off)

On a side note the tests on page 16-6 were/are done with the icm unplugged so the primary coil test is just testing the wiring from icm to coils? Should I unplug the coils when I do this test? I left mine in to try to test the total resistance with coils I can go out and rerun the test with the coils off if that's how it should be done. I was getting between 4.3-4.5 ohms seems way high and seems like a good starting point for no spark problem but I'm not sure how to remedy it.

Hi , its just testing your primary and secondary windings, heres a good video, of course take your own manual specifications.
also have a look at this, give a shout back when you've got as far as you can

Yeah I started out with testing the individual coils and I got 3 ohms for the primary coil and 24.1k ohms for the secondary. I got the same results for both coils and both are in spec according to page 16-7 in the manual. So with that, good spark plugs and spark plug wires I don't think that the coils them selves or the plugs or plug wires are the problem.

The icm gets power, the pulse generator is working and tested, the neutral switch side stand switch and ground are all good at the icm according to the tests done following page 16-6

Back to the question I had earlier what the difference in the tests on page 16-6 for the ignition primary coil and the tests done on page 16-7, one tests the coils unplugged from the main harness and the other tests the resistance with the coils plugged in but the icm unplugged. So if I know the coils are good according to 16-7 and I fail the ignition primary test on 16-6 that would show that the resistance in the wires between the icm and the coils is too high? thats why I'm thinking I need to rewire with thicker gauge wire? let me know where or if I'm wrong with my thinking maybe I'm just not thinking of this in the right way

On a side note if someone could run the same test with the icm unplugged and the coils plugged in what resistance do you get? Then once with both the icm and coils unplugged and see what you have, I can do the same and see if it really is just the resistance in the old hacked up wiring or if a part is bad

Hi Tampa, think probably you are over thinking it, tests look fine to me , maybe start to look for another cause, have you tried with parts back together and give it a start, if there is an intermittent spark and you have new plugs, have a look at the earth at the coils, evidently with getting a spark it has to be wiring somewhere on your bike that's shorting intermittently, I know its a pain but check all handle bar switches especially the kill and starter for cleaness(no rust):icon_wink:

Put in a new battery after having the other one tested and determining it was bad, I'll pull out the kill switch today and make sure the connection is strong and solid, I have tested the switch via multi meter and it was working on a continuity test but maybe the connection is weak. I know the side switch and neutral are both good I have triple checked those, stock timing and pulse generator has been tested and is working

How would I go about testing the ground at the coils? Other than pulling a plug wire putting in a new spark plug and grounding the threads against the block? That's what I'm doing to see spark. But the coils only ground out through the spark plugs and back through the icm, but I have never actually looked at the icm circuit so I'm not sure if the coils ground out the or not but the ignition wiring diagram shows the icm grounding. Only coil tests I'm aware of are the ones listed on page 16-7 and they both passed those tests

I'll post up what I find after I get to it today

Pulling the plugs and testing them against the body is the best way to make sure you have a spark, don't know if you've had the connecting wires off the coils , but just in case , and an easy mistake to make the diagram and which wires go to which coils , could be the firing order isn't right

Ok the kill switch and start button are exposed both have strong solders and pass continuity multi meter tests. I tried to start again all connected and I didn't get spark from the 1 or 2 piston so no spark at all from either coil

I know it's not the coils they passed the tests from the manual page 16-7

So it's upstream from that, I know the neutral switch side switch kill switch start stop button works the coils work, new spark plugs good plug wires

I'll test the starter relay, the only other problem I'm having is sometimes when I press the stat button everything stays on just dims out if I turn the key off then on it will either dim again or start but when it starts there's no lag it's a brand new battery on a tender so it's not a dead battery with no juice to turn the motor. This problem also shows a potential wiring problem.

Only test I can find that my bike doesn't pass is the ignition primary coil test page 16-6 for the icm, it calls for a max of 3.1 ohms I have a low end of 4.3 ohms over a ohm difference. Those lines from the icm power the ignition coils if there's too much resistance maybe the coils aren't getting enough juice to create spark?

I'll go out and test the starter relay in a few minutes

Is there anyone you could borrow a ICM off to test your bike, as there is no way of testing your own ICM