Running problem at idle --on the road

[movenon]

On the coils all I have is the spec's.

Primary side (low voltage side)  2.7 ohms +- 10%

Secondary side (high voltage side, plug side) 12K +- 20%  Measured from plug wire to plug wire not plug wire to ground.

Spark Plug caps 10k +-10%    Plug caps are resistive.  RPM has these. 

Plug wires are solid core (non resistive).  I replaced mine with over the counter wires from NAPA. 

Min spark  6mm (.24)

Glad it held up for the ride. 
George

[markmartin]

I finally got some time today to look into the issue and after some poking around, found 2 possible causes.  


1.)  This picture is the connector from the (key) ignition switch. It was badly corroded and the plug housing was melted.  I replaced the melted plugs with blade connectors, crimped, soldered and heat shrink tubed.



2.) While changing the oil and installing an RPM oil filter adapter, I found the kickstand switch wire crimped and showing wire.



I also serviced the kill switch.  It looked OK, but I polished up the contacts, hit it with contact cleaner, di-electric grease and reassembled.

The charging system seemed to check out fine, with the battery at 13.3 volts sitting, 14.9 volts running at 3000 rpm.

As for the ignition, the pick up coil resistance was within spec at 174 ohms.

The ignition coils both came in a hair low at 2.3 ohms with the factory spec at 2.4 -3.0 ohms. I don't know if this .1 ohms low reading is an issue. Also, I didn't check the resistance of the plug wires....


To Jpaganel, thanks, I do have a jumper from the negative terminal on my battery to the bolt that holds the fuel tank as a second ground, but thanks--it definitely could be a ground issue. And your ground assembly looks better than my negative jumper to the tank bolt --nice job and thanks for the picture.

Pat, thanks for the great idea.  If I continue to have this problem, your suggestion about jumping directly to the igniter is my next move. The clutch and kickstand switches have not been taken apart yet. Jumping directly to the igniter box would by pass those.  BTW, Does anyone know if the clutch and kickstand switches can be taken apart and cleaned??


I'm hopeful that the melted connector, the kill switch, or the crimped kickstand wire was the source of my problem. We've got an 800 mile trip to the north shore of the St. Lawrence Seaway  coming up soon, so it should be a good test.

[markmartin]

For the sake of closing this thread with a conclusion, it seems that my problem was indeed an electrical issue as detailed in the prior post.  I put 900 miles on this past week with no stalling issues.
Thanks to all who contributed advice in my time of need.

[Pat Conlon]

Very good Mark! 

[markmartin]

After finding the melted connector at the ignition I thought I had solved my problem and put 1000 miles on with no issues.  The problem has returned.  The bike dies at idle usually when coming to a stop.  I did notice that the clock goes out when the bike dies.  It usually will start right back up like noting ever happened, but occasionally it remains dead for a few seconds--while it is dead the clock is out--when the clock comes back on the bike will turn over and start.  It runs perfectly when it's running.

I'm going to strip the fairing off it this weekend and start looking for loose connectors or frayed wires. 

Any suggestions on where to start looking?  What would kill the ignition and kill the clock?? 

[JPaganel]

Any suggestions on where to start looking?  What would kill the ignition and kill the clock?? 

Grounds.

Bad grounds are the bane of any older vehicle, and doubly so of an older bike.

Check the main ground wire, the negative from battery. It bolts to the frame down in the bowels, under the carbs and the heatshield. The lug can corrode and give you bad ground. Shine that bastard up.

[ribbert]

After finding the melted connector at the ignition I thought I had solved my problem and put 1000 miles on with no issues.  The problem has returned.  The bike dies at idle usually when coming to a stop.  I did notice that the clock goes out when the bike dies.  It usually will start right back up like noting ever happened, but occasionally it remains dead for a few seconds--while it is dead the clock is out--when the clock comes back on the bike will turn over and start.  It runs perfectly when it's running.

I'm going to strip the fairing off it this weekend and start looking for loose connectors or frayed wires. 

Any suggestions on where to start looking?  What would kill the ignition and kill the clock?? 

Chances are when replacing the connector you have disturbed the dodgy wire and brought it back to life, for a while! You will probably find the tacho is dying as well when the motor cuts out.

Intermittent electrical problems can be a fair bastard to track down, for just that reason, they're intermittent and when you're checking continuity, you have no idea what state it's in at that moment.

If you can get it to idle and with as much access as possible (tank and seat off at least) start prodding and pulling the wiring loom, anywhere and everywhere. If you have a poor connection, this should cause it to act up and help locate the general area. Start with the most obvious, the battery leads.

If you can't get it to start and idle, do the same thing but with a test light and illuminating continuity tester. Multimeters are not the best tool for this job, it's too easy to miss the flicker of the screen.

This is a methodical process of elimination, not a hit and miss affair and will eventually home in on the problem.

The worst one I have encountered in a long time was on my own bike a while back, only happened at road speed, so couldn't be duplicated in the garage.

Turned out to be an unsupported wire running behind the battery box, with an in-line fuse, had an internal break and no external clues. The weight of the fuse holder was blowing around in the wind as I got up to speed, making and breaking the connection rapidly, as soon as I slowed and the wire stopped blowing around, it was fine again.

Let's hope it is something simple and easily found. From your description, it certainly sounds like a dodgy connection.

Good luck.

Noel

[ribbert]

Forgot to mention, test lights with a hardened, surgically sharp tip make any tracing job a lot easier, That is sharp as in draws blood when you press it on your finger in the shop to see how point it is.
You can also poke through insulation at various points along a wire.

[markmartin]

Update: I stripped the fairing off and expected every wire, connector, and fuse and cleaned and di-electric greased every connector.  I did get to the main ground connection, and it looked great but I cleaned and brushed it for good measure and , as suggested, shined that bastard up. I didn't find anything definitive, however I did find a couple of suspicious pinched and kinked wires and a couple of half blown/discolored fuses on my auxiliary light and auxiliary heated jacket harnesses.

The good news is that I've put on about 200 miles and the problem of cutting out at idle is gone, hopefully for good this time.

[Country Joe]

Forgot to mention, test lights with a hardened, surgically sharp tip make any tracing job a lot easier, That is sharp as in draws blood when you press it on your finger in the shop to see how point it is.
You can also poke through insulation at various points along a wire.

I'm glad to see that in not the only one to have a blood letting session with a test light.

[momodasaint]

I'd like to add to this discussion even though it may be fixed, someone else reading this thread may find it helpful.
I had an FJ1100, 1984 model that would intermittently stall or run badly.
After many different options tried, I eventually discovered that the '84 FJ1100 had a rev limiter fitted to the dash. This limiter was sending a signal to the cdi, which was shutting the spark to 1 & 4 thinking that the bike was over revving. The solution was to cut the wire that sent the signal from the dash to the cdi.