Topic: Ignition cut out on me 4 times this morning

[RandomOrbit]

As the title says, my ignition cut out 4 times while riding to work this morning. First time buzzing along in the left lane at 5000+ RPM. I remembered something like this happened once before and turned out to be just the ignition key wasn't quite clicked into the detente so I reached down to wiggle it and it snapped back on maybe even before I touched it.

So I'm cruising along, and it happens again and I reach down for the ignition key, but nothing happens. So I roll off to the shoulder, and I see no lights, so I'm thinking maybe the main fuse is blown. I take of the side cover and fusebox cover, and nothing looks blown. I take out the main fuse and put it back in. Turn on the ignition key, and the lights are all on, but I kick it a few times and it doesn't want to start. I put on the choke even though I know It's plenty warm. Give it a kick, heart a little pop, turn off the choke, and kick it again and I'm back on the road. Until...

Not much more than a mile down the road it happens again. When I coast over to the side I see the lights are still on, so I kick it and start up and get back on the road.

Fourth time similar to the third, except I kick it a bunch of times and it doesn't seem to want to start, then I hear the little pop and it starts up and I get back on the road again.

At this point I was about 36 miles into my 40 mile commute and I made it to work without another incident, but I'm kinda wanting to sort it out before I head home again tonight. I'm thinking it's likely a funky contact somewhere because when it comes back on it runs fine. Maybe it's the ignition switch, but that is a NOS Honda part installed 2 years ago, so it's not like it's old and crusty. Another possibility I suppose is the ignition which is a Dyna S about 16 years old. I know those act up in the heat sometimes but it was 42º when I left this morning, and still only 55º when I got to work. So it's not hot.

If it's the switch I'm thinking if I squirt WD40 in the keyhole it will make short work of that. If it's the ignition module, there's probably not much I can do. Otherwise maybe it's a contact somewhere. Anybody have any ideas where I should be looking? Ignition switch block obviously.

[rotortiller]

I had the same issue several years ago on two bikes. I took my switch apart cleaned and secured the loose contacts where riveted to the wires. I used a bit of solder to wick in. Been great since. When it quits next time wiggle the harness at the backside of the switch (and/or the key) and watch the lights for flicker.

rt

[evinrude7]

on the dyna s does it run 1-4 and 2-3 separately like a regular old points plate or is it all or nothing? 

[calj737]

on the dyna s does it run 1-4 and 2-3 separately like a regular old points plate or is it all or nothing?

all ignitions on our SOHC are wasted spark, 2 coils, 2 cylinder pairs.

[RandomOrbit]

on the dyna s does it run 1-4 and 2-3 separately like a regular old points plate or is it all or nothing?

all ignitions on our SOHC are wasted spark, 2 coils, 2 cylinder pairs.

Yes it's basically 2 magnetic pickups (not sure if that's the correct terminology) replacing the 2 point sets.

[RandomOrbit]

Another thought: I yanked the tank last night to install a new tach cable, and it was already getting dark when I put the tank back on. I should probably make sure I didn't pinch any wires.

[Deltarider]

Another thought: I yanked the tank last night to install a new tach cable, and it was already getting dark when I put the tank back on. I should probably make sure I didn't pinch any wires.

Always start with suspecting what ever you've touched last.

[RandomOrbit]

Another thought: I yanked the tank last night to install a new tach cable, and it was already getting dark when I put the tank back on. I should probably make sure I didn't pinch any wires.

Always start with suspecting what ever you've touched last.

Well I DID, but I was like "I don't think it's the new tach cable..." Sure am glad I didn't install the new regulator/rectifier last night, because I'd be suspecting that, but it can't be doing any harm sitting in it's box on my back porch. I always worry about that dang wiring loom though that wants to get tangled up in the tank mounting rubber, and the ignition switch plugs in right around there as well.

[BomberMann650]

It’s an interesting sensation when a cb drops out two cylinders
Are you having voltage/power issues and are just waiting to install the reg/rec?  Voltage drop could be effecting your dyna.

[ekpent]

 I got left high and dry on a K2 750 once. Bike just died and no ignition. When I pulled the tank the ignition switch plug had pulled out just enough t kill it. I had one of those relocation switch plates up by the triple clamp and those can max out your wire length sometimes.

[RandomOrbit]

It’s an interesting sensation when a cb drops out two cylinders
Are you having voltage/power issues and are just waiting to install the reg/rec?  Voltage drop could be effecting your dyna.

Charging is a bit on the weak side. Bike always starts and runs, but doesn't keep the battery topped off. So for instance if I switch the ignition on but don't start the engine, there may not be enough juice to blow the horn, and the starter motor runs a bit sluggish. But I'm in the habit of kicking it, so that never seemed like much of a problem. Once running at idle the horn will blow, and if I rev it to 3000 I can see the headlight get brighter, but it never really charges up. Once this summer I left the headlight on and killed the batter entirely, so I put it on a charger, and the charge held a couple weeks before returning to status quo levels. I've run it all summer like this over 3000 miles. So the charging system is working, just not well.

I figured a new Reg/Rectifier was probably a good idea, so I put one in my latest parts order which arrived last night along with the tach cable, but I didn't have time to install anything other than the tach cable last night.

[754]

Mine was not working one morning,  i oiled the key a bit with the dipstick , then it worked fine.
 It helps if you take switch out of the bracket under tank  put keyhole up,  then oil the key.
 I would not spay in there,  hard to control, how much gets in.

[TwoTired]

Give it a kick, heart a little pop,

Clue.  When you hear the pop, the dyna has just gotten power again. 

I'm thinking it's likely a funky contact somewhere because when it comes back on it runs fine.

Likely.

If it's the switch I'm thinking if I squirt WD40 in the keyhole it will make short work of that.

I wouldn't rely on that.  Magic liquids have severe limitations. Lubing the key tumblers has little effect on the electrical contacts, even if there weren't a Separator inside.

If it's the ignition module, there's probably not much I can do. Otherwise maybe it's a contact somewhere. Anybody have any ideas where I should be looking? Ignition switch block obviously.

Look at the back of the fuse block solder connection.  REPLACE the fuse.  As they can part under mechanical and heat stress the end cap connection where line of sight is difficult.  Check for that anyway.

Cycling the key switch can sometimes re-establish ify connections inside.

To get home, you can hot wire the bike.  All you need is to connect ANY black wire, to the Battery POS terminal or the equivalent hot side solenoid post, perhaps to the Vreg black connector nearby.  This will bypass both the key switch and your fuse block.  So, not a long term solution.

Since the lights go out with the ignition, it is more likely a power pathway issue.

Cheers,

[RandomOrbit]

So I went out on my lunch break to try and check it out. Took the tank off and put it on the curb, and found that while it wasn't actively pinched by the tank, the connector  cable for the ignition switch was fairly taut. So I took the connector apart, and belw both sides with canned air. The switch side looked new and shiny as I'd expect, but the wiring harness side was fairly dirty and corroded looking. So I scraped it out a bit with my pocket knife and wiped it with an alcohol based wet wipe and blew it out again. moved the harness around a bit to try to create a little more slack and put it all back together.

Nothing conclusive, but given that was the thing most likely to have changed since the last time I rode, it, and given that I know disturbing electrical contacts on this thing does tend to lead to previously good contacts going bad, I think it's a good bet. I also took the points cover off to visually inspect the ignition wires which looked fine, and not strained. Blew that out with canned air while I was at it, then put it all back together and took it for a short and uneventful spin. Fingers crossed that that took care of the problem.

I don't think it's likely that the problem is with the ignition switch itself as it still looks very clean and shiny. SO if it is, then it's a more likely to be a manufacturing defect than a dirty contact.

I ordered some of this Deoxit stuff last night which i intend to use sparingly on electrical connector contacts moving forward in hopes of taking care of some of the oxidation and grime.

[BomberMann650]

Try crusing at a higher rpm on the way home.  Especially since you admit your charging system output is on the low side.

[Bankerdanny]

If it were key related I would think that you would lose all power. If the lights are on then it isn't likely a key problem.

As far as the overheating ignition goes, the unit is hidden under a cover and it is the engine that generates the heat not ambient air temps. When the EI was failing on my 550 I pulled the points cover so that air could circulate over the ignition and cool it

[PeWe]

Replace ign switich just  for sure if you think its bad. Get a stop on a remote road cost much more than an ign switch. My stock ign switch fell apart in early 80's. I replaced it with a hidden switch under the tank, ON-OFF.
My bike got a real switch again 2013, riding season 2014. Cheap copy so it got a relay feeding the coils. 2 more relay for head light (hi-lo).

Try std point plate, the old tech. Electronic stuff can get intermittent dysfunction, especially when warm.

[RandomOrbit]

Replace ign switich just  for sure if you think its bad. Get a stop on a remote road cost much more than an ign switch. My stock ign switch fell apart in early 80's. I replaced it with a hidden switch under the tank, ON-OFF.
My bike got a real switch again 2013, riding season 2014. Cheap copy so it got a relay feeding the coils. 2 more relay for head light (hi-lo).

I went through 2 of those cheap $8 Emgo ignition switches over the years, and used a radio shack toggle switch a couple times as well. Bought a new Honda OEM switch and seat lock a couple of years ago because I was sick of the cheap ones wearing out, and I wanted my seat and ignition lock to match again.

I don't think there is anything wrong with the ignition lock itself, but if there is I'm going to want to match the new one to my existing key, because I know there is nothing wrong with the seat lock.

[RandomOrbit]

No further incident on the way home, so here's hoping cleaning the ignition switch connectors did the trick!

It felt slightly stronger too, though it's hard to know if I'm just imagining that, but it is idling better.

[evinrude7]

Try crusing at a higher rpm on the way home.  Especially since you admit your charging system output is on the low side.

this. 

[RandomOrbit]

Try crusing at a higher rpm on the way home.  Especially since you admit your charging system output is on the low side.

this.

My commute is 40 miles and I'm cruising above 5000 rpm for 38 of them. You really think dropping into 4th is going to make it charge any better?

[TwoTired]

Try crusing at a higher rpm on the way home.  Especially since you admit your charging system output is on the low side.

this.

My commute is 40 miles and I'm cruising above 5000 rpm for 38 of them. You really think dropping into 4th is going to make it charge any better?

Well, you won't really know until you do the rpm vs voltage output test, will you?

[RandomOrbit]

Try crusing at a higher rpm on the way home.  Especially since you admit your charging system output is on the low side.

this.

My commute is 40 miles and I'm cruising above 5000 rpm for 38 of them. You really think dropping into 4th is going to make it charge any better?

Well, you won't really know until you do the rpm vs voltage output test, will you?

According to this chart, the charge rate in a properly functioning CB750 system maxes out at 4000 RPM. So I think it's unlikely that pushing it from 5000 to 6000 rpm will be of any help, and I suspect that running in 4th at 80mph for 38 miles is likely to do more harm than good. I mean I know it can lope along quite comfortably at 6000, but I don't think it's going to help anything. Also while I haven't put a voltage tester on it yet, I HAVE run it at 6000 rpm plenty with no notable difference in battery charge state.

I don't mean to be too argumentative, I do appreciate everyone's input, but according to my understanding running at higher RPMs to maintain a charge is more relevant for around town stop and go driving with a lot of idling, and not particularly relevant to when you're talking about riding 80 mostly highway miles in a day.

Anyway if the charge state of the battery was related to the ignition cutting out it was as an additional symptom of corroded contacts, and not a cause. The charge did not seem to improve on my way home today, but it did seem to run better, and idle was a few hundred RPM faster at stoplights the at end of my ride than it has been lately, so I had to adjust the idle adjuster screw down. Not sure why that should be, but maybe cleaning up the contacts allowed the ignition to run stronger than it had been. I expect replacing the regulator/rectifier should take care of the charging problem, and that's on the agenda for this weekend.

[HondaMan]

Hmm...I'm thinking this sounds like you need my Fuseblock?

Pull out the fuses (disconnect the battery first...) and clean their contacts with a small penknife until they shine. Shine up the fuse end caps, too. If this fixes it, you need my fuseblock...

[TwoTired]

Try crusing at a higher rpm on the way home.  Especially since you admit your charging system output is on the low side.

this.

My commute is 40 miles and I'm cruising above 5000 rpm for 38 of them. You really think dropping into 4th is going to make it charge any better?

Well, you won't really know until you do the rpm vs voltage output test, will you?

According to this chart, the charge rate in a properly functioning CB750 system maxes out at 4000 RPM. So I think it's unlikely that pushing it from 5000 to 6000 rpm will be of any help, and I suspect that running in 4th at 80mph for 38 miles is likely to do more harm than good. I mean I know it can lope along quite comfortably at 6000, but I don't think it's going to help anything. Also while I haven't put a voltage tester on it yet, I HAVE run it at 6000 rpm plenty with no notable difference in battery charge state.

I think you missed the point.

The chart is not installed on your bike, and neither the alternator or the battery can't read it, anyway.
The chart assumes your bike is working as it should.
How do you know it is working as it should?

Clearly you have doubts, or why would you be replacing the Vreg?

Say your alternator system has diminished capacity, and it actually puts out 3/4 or 2/3 of what it should.  A new regulator won't fix and bad connector phase wire, or a faulty connector reducing the voltage to the regulator/alternator field coil.

An RPM/ voltage output test, determines the health of the system you have now.

Yes, it should peak at 4000.  What if YOUR example peaks at 5000 or 6000?

Cheers,