Hey guys- I've got a '91 F2 with an interesting no spark issue. I've had this bike for 2 years and put about 12k miles on her. Here's the story:

About 4 months I moved between islands (Hawaii) and brought the bike over on a barge. It definitely got a good little spray of seawater on the way over and I gave her a good wash down after arrival. It was after arrival that a hard start problem began. The bike would start but I had to crank her several times before getting her to start. When I took off plug wire no. 1 and did the spark test there was no spark until she finally started. As soon as a spark shows up, she starts. I've been riding her over the past four months just living with the hard start but it appears to have gotten worse as now I have drained the battery several times and had to jump to get her to start. The same problem persists when jumped from the Napa battery charger.

Once the bike starts it runs fine- no backfiring, normal power but the one thing I have had happen is the engine will turn itself off as I'm coasting into my parking spot. Has never turned off in neutral at a stop light but only when coasting into my parking spot at work (or home) with the clutch pulled in. Lights stay on when this happens. I've also noticed that it is easier (still hard start) when the bike is cold but if I just rode for 15 minutes, shut it off, then go to start it again, it is even harder to start (and the battery usually will die before it starts).

So far I have:
Checked resistances on ignition pickups- within spec when cold (72 deg),
Checked to see voltage pulse from pickups with DMM upon start,
Replaced spark plugs with iridiums,
Replaced ignition coil packs with new,
Replaced spark plug wires with other used ones with less resistance,
Replaced CDI with another used one,
Checked resistances of coils (primary and secondary)- within spec,
Checked kill switch connections- solder looked good,
Checked oil level (but not indicator wiring- no oil light on (but I guess bulb could be out)).

Still same problem.

I haven't checked the neutral/side stand diodes because the indicator lights work fine and I have tried starting her with and without these configurations and it doesn't make a difference.

I'm going to go take a look at the oil pressure gauge wire and also look at the relay connected to the ignition power supply today.

Is is possible the starter is drawing too much current and the coils aren't getting enough?
Could there be something wrong with the ignition switch? My friend told me one time his car wouldn't start because the key wasn't contacting correctly.
Anyone had a similar problem or have any suggestions?

Much Mahalos

 

i mean i kinda had the same problem but mine i'm pretty sure was due to a ignition coil from a golf kart, spark plug wires from **** (ya i don't know either) a burnt out stator and rectifier

 

Well you're right I haven't ruled out the stator yet but it did test within spec on resistance and I did see a voltage pulse with my dmm so I'm a little hesitant to replace it right now. From the wiring diagram it looks like the rectifier's only duty for a start is feeding the starter relay. Since my starter appears to be working solid I'm not inclined to go that route either.

An update: all wiring (outside of the harness is in good shape) and all connections good.
Oil pres switch wiring good (and has no cutoff for ignition) it triggers the warning light only
The neutral diode tested good
I traced the wiring to look for the relays coming from the kill switch but haven't found them yet. They must be up behind the gauges.

Another note about the bike: it had been used as a stunt bike by one of the previous owners and the ignition switch has some visible damage (the key wobbles around when inserted). I played around with starting the bike, warming it up, turning it off, turning back on and jiggling the key around in the switch. It would start when warm after the key was jiggled back n forth. I ordered a new ignition and key so I'll pop that in and I'll report back! I've got my fingers crossed but I'm going to keep riding it and jiggling the key. Hopefully it will become more apparent!

 

Well, no luck with the new ignition switch. Installed the new switch a few weeks ago and rode the bike since then. Still the same 'ol problem- hard start due to no spark. I never did find any relays in the ignition circuit- only the starter relay.

I originally eliminated the battery as a problem because the same symptoms occurred when the battery was hooked up to a charger/jump starter. Could a bad battery still be causing this issue, even if the charger is hooked up to the posts?

 

...my vote would be the battery...unless you got close to 13volts and all it's doing is cranking fairly fast but not firing... starter relay?..check you ECM connections?...

 

After going through everything in the CBR Service Manual, I found an electrical troubleshooting manual and started running through those tests. I know for fact that my charging system is functioning properly because several times I have nearly drained the battery completely and recharged it by riding around.

I ran through the tests on the Reg-rectifier and it passed all.

I ran the test for voltage leakage from both positive and negative terminals. Test criteria was less than 0.2V for each. Negative passed. Positive leakage was around 0.25V. I cleaned the connections between + battery terminal and R/R.

I measured resistances between the 3 stator leads. Criteria was between 0.5 and 2 ohms. They measured 0.3, 0.3, and 0.4 ohms. This makes me think the stator is the most likely culprit.

I also checked the resistance between each stator lead and ground and measured OL (passed).

I'm tired of replacing parts in hopes that the next will be the last. Any way I can confirm the stator is at fault?

 

Just looked back at the service manual- apparently acceptable resistance for the coils is 0.1 to 1 ohms. Therefore it looks like the stator is OK.

The one other test the other manual told me to do was test the AC voltage between each pair of coil windings with the engine at 5k rpm and if they were unequal or less than 100V, then the stator is faulty. I did this test and all pairs measured equal but around 10.89V (I measured at the R/R with the R/R still attached). Not sure if I did this right- I was thinking with the R/R still hooked up it might have lowered that voltage but either way it seems to me like the stator is probably working just fine (at least when the motor is on and working fine). Since my problem is during start only (usually- it's only cut off on me a few times) I can't really 'catch it in the act' for that test.

I'm at the end of the road here. I think I've done every test of the electrical system. Although I've tried starting the bike straight from the battery charger I'm going to take the battery off and see if I can get it load tested at Napa.

The only real flag that popped up during testing was that leakage from the positive battery lead. Any tips there?

Other than that I'm still stumped. Not looking so good for this bike's future.

 

Just took the battery to get load tested. It's cherry. Can rule that one out. Well I'm stumped. I'm going to take it to the shop Monday.

 

It was the kill switch the entire time. I'm kicking myself for not catching it months ago. I bypassed the kill switch today and bam- it started up first thing several times in a row. Took the switch out of the housing and there was some corrosion on the copper switch connections. Cleaned them off and popped it back in and now she's good as new! Didn't know such a simple 2 way switch could throw me on such a long goose chase- well lesson learned- check all connections means check ALL connections- especially when high corrosion environments are a factor.

I never did take it to the shop- stubbornness paid off in the end. Aloha for the help and I hope someone else finds this thread useful!