Well...I'm back. After replacing the "under the fuel tank" connector - which resulted in the bike running great for about 2 weeks - just a few days ago, I was riding to work, and about 5 minutes into my ride, the engine stalled out. I let the bike cool, and for the next hour, I attempted to start it without success. The next day, the bike started right up...I let the bike idle for a few minutes, then I kept it revved at about 2500 to 3000 rpm...after about 6 minutes (I used a stop watch), the engine stalled. I let the bike sit for about 4 hours...started right up again...I repeated the "revving test"...sure enough, after about 6 minutes, the engine stalled...and this time, the bike was sputtering for the first few minutes.

After I replaced the fuel tank connector and got the bike running a few weeks ago, I did the hair dryer HES test...no issues. The wires of the HES also looked really good...like new. I have read that early K bikes had "vapor lock" issues.?.?

Before spending the money on replacing the HES, are there any other potential "engine goblins" I could search for?

Thanks in advance...

Rob

Coils?

  They tend to quit once hot, if going bad

It would be interesting to test the Hall sensors just after the bike stalled. The hair dryer is a good test, but it may not provide enough heat.
As the bike takes a long time before it restarts, this gives you enough time to remove the tank and access the connector.

Another weapon in the battle with semiconductors which are suspected of breaking down when hot is freezer spray. When the fault is present, hit the suspect with a shot of spray and see if it starts working again.

Avenger GT wrote:Another weapon in the battle with semiconductors which are suspected of breaking down when hot is freezer spray. When the fault is present, hit the suspect with a shot of spray and see if it starts working again.

I believe that you are the first one giving this solution, and this is a lot faster than removing the tank to access the HES connector.
It also has the advantage of concentrating on only a specific portion of the circuit.
This method of troubleshooting could also apply to the coil.

Crazy Frog wrote:

Avenger GT wrote:Another weapon in the battle with semiconductors which are suspected of breaking down when hot is freezer spray. When the fault is present, hit the suspect with a shot of spray and see if it starts working again.

I believe that you are the first one giving this solution, and this is a lot faster than removing the tank to access the HES connector.
It also has the advantage of concentrating on only a specific portion of the circuit.
This method of troubleshooting could also apply to the coil.

So...silly question...and forgive my ignorance...where exactly would I spray the freezer spray as it relates to the Hall Sensor and the coils?

robdiaz44 wrote:
So...silly question...and forgive my ignorance...where exactly would I spray the freezer spray as it relates to the Hall Sensor and the coils?

Sorry, I didn't answer your question.
First, you will start with spraying the HES, and then if it doesn't produce any positive result you will spray the coils(maybe one at the time).
The goal is to find in a really short time which component fails under heat(before the natural cooling occurs and the bike starts again).
The advantage of carrying a can of freezer spray in your tool box is that you could troubleshoot very quickly on the side of the road, and if you find the failing component you could cool it down in order to ride again to your work shop to replace the culprit.

Thanks so much Crazy Frog, Avenger and Steve...I will find me some freeze spray and get on it.

So, I have a friend who does some bike mechanic-ing...he took my bike to his shop. He started it up and let it idle...and, sure enough, after about 6 minutes, it stalled out. He pulled the number 1 spark plug wire off, put an older plug in the wire harness and just let it hang against the bike. The bike started up...the bike idled okay on 3 cylinders for about 15 minutes, never stalling out. He shut the bike off and, with the same set up, restarted it a few minutes later...same thing, idled for about 15 minutes without stalling. To note, the cooling fan cycled on and off a few times - he didn't think the issues was HES since the engine got hot enough for the fan to cycle a few times. Also didn't think the coils were the issue. We're still scratching out head. He was next going to start checking the ignition wiring...any other ideas?

Thanks,

Rob

Have you checked valve clearances? Maybe the gaps are too narrow, causing these problems as the engine warms up.

Heat seams to be playing a factor and as far as I can see there are only 3 parts that would cause the motor to stall when hot. HES, HT (coils, leads & SPs) and valve clearances.

If you think you've ruled out the HES, then checking the impedance on the coils, leads & SPs would be next imo. Easy to do. SPs can seem to spark just fine but under compression and at high temps they can fail miserably. Have you pulled the SPs? If one or two are fowling they could be dud.

Checking exhaust valve clearances as rob suggests would be the next bet.
Q. When it starts to stall, can you keep the motor going by giving it a little throttle to keep it above 4k then throttle off and it dies?? If so, then its gotta be exhaust valve clearances imo.

Coils, SP's and leads look good...haven't yet checked the valve clearances yet. But, my mechanic buddy put the SP lead #1 back on and the bike started right up and stayed idling for a long time (15 to 20 minutes).

While the bike was idling, he checked the voltage reading on the battery...it gave readings anywhere from 10 to 16.

He took the voltage regulator off to look at and measure the brushes...they were about 5mm. I will definitely be getting some new brushes for the regulator. Question is...could this be causing the stalling issue? Mind you, it never stalled out during the time the bike was idling and/or being revved today (engine got hot enough that the fan cycled on and off a few times)...not sure if heat is the issue anymore. He commented that he was revving the bike pretty high, which allows the brushes to "seat" better than if it was revving at low rpm (which is how I typically ride the bike as most of my riding is in the city - stop and go riding).?.?

quick answer is yes

if the bike is idling under 1100 or so ...and the battery lamp has not extinguished *( a quick rev can get over this issue )

the voltage can decrease to a level where the whole system crashes somewhat

yes get a new regulator

yes clean all the contacts on the alternator properly ...including the little finger that connects to the field exciter terminals on the alternator

 

some times a clean up of the commutater rings is also required ...some really fine wet and dry (1200) could clean then up


good luck

robdiaz44 wrote:......

While the bike was idling, he checked the voltage reading on the battery...it gave readings anywhere from 10 to 16.
......

Check the charge voltage across the battery at >2000rpm. Taking a reading at idle doesn't mean anything.
You should be getting something up around 14 volts and it should be fairly stable.

Could it be that the #1 lead was not making proper contact with the SP? Do you have connectors screwed to the top of your SPs?

I'm not sure that cleaning the slip rings is a good idea. Clean any crud around and between them but not the rings themselves (unless there's obvious signs of lumpy build up of dirt). The reason being that the copper doesn't have a perfect surface - it's full of minute pits - and those pits get filled in with brush graphite. This gives a better surface for the brushes to run on and - in theory - reduces brush wear over time.

I am not too keen on using the wet/dry sand paper as the grit embeds into the copper. I always use a lathe to clean them up and if it needs to have more than 1mm removed chuck it. I cant remember if it was here or the Kawasaki forum where someone used emery tape and it now eats a set of brushes for lunch each day.

When I worked at a company that refurbished computer equipment, they used an ink eraser to clean contacts. It is abrasive enough to clean off corrsion but left no residue behind and did not change the electrical characteristics. Pencil eraser won't work the same though.

Kaptain Holister wrote:Check the charge voltage across the battery at >2000rpm. Taking a reading at idle doesn't mean anything.
You should be getting something up around 14 volts and it should be fairly stable.

Could it be that the #1 lead was not making proper contact with the SP? Do you have connectors screwed to the top of your SPs?

Thanks all for the feedback...

* Kaptain: I actually mis-spoke what was going on: the bike wasn't just idling...my friend was "idling"/revving it much of the time between 2000 to 3000rpm, then at various times opening it up to 5000 to 7000rpm. Most of the time, volts were fluctuating between 12 to 13.4...never stabilizing in that 13.8 to 14 range. Also, not sure if I have connectors screwed to the top of the SP's...I will check that.

* Charlie: Are you recommending that I replace the voltage regulator rather than replacing just the brushes on my existing regulator?

The voltage regulator and brushes are the one unit. 5mm is the limit on the brushes so the unit needs to be replaced. The best I've found is from EME.

The low/fluctuating charging voltage would be the wornout brushes but the voltage regulators don't last either. I think that's why they designed the regulator and brushes together so it would get replaced regularly.