I guess I'm not clear on this "computer resetting" part described here. Are we just talking about something in the electronic instrument panel, or we talking about a computer like an FI vehicle has?

 

With a bad battery the DC voltage will collapse and your computer will turn off. Putting the bad battery on a charger will bump the voltage back up to a usable range, but it will dump again over time. A voltmeter will diagnose this pretty quickly. What kind of numbers did you see? Open circuit, charging on the bike, and under load? Open circuit is over 12.7V, charging is over 13.5-14.5V, and under load should not drop below 10V. If the battery checks out ok, then the charging system may have an issue. This is masked since you're charging the battery off the bike. The 3 tests above should tell you whats up. A bad connection to the DC supply will also cause the computer to turn off. Your kill switch could be messed up, but that wouldn't cause the computer to turn off. Your ignition switch could be it. Start eliminating possible causes.

 

Lotrat: All of the above measurements have been normal, within the same limits you said, on the batteries (both the old one and the new one I bought just in case). Open circuit, for some reason, I'm reading very slightly lower than 12.6/7... the new battery actually reads 12.3V, even after a full trickle charge (and when it was right off the shelf). Can that tiny difference be a problem? It still cranks the starting motor and everything just fine, I've really begun to think there's no way it's the battery because of these factors (along with the fact that I can't even reliably start it anymore with a car battery or jumper box).

TNC: By "computer reseting" all I was talking about was the fact that the computer literally flashes off then back on sometimes when it stalls... and the trip OD's and clock both RESET! That one fact seems to tell a lot... in order for that computer to reset, there has to be some complete interruption of power going to the computer at various times... and that sure seems to me to indicate a loose or bad/fading connection wire somewhere.

I'm about to head out back and start checking continuity in every wire going to the computer that I can find, and hopefully I'll learn something... if not, I'll figure out how to test the ignition switch maybe.

Here's one thing that is driving my mind crazy in terms of it being a loose/bad connection though... if something is losing continuity and causing the problem, why isn't it the same symptom every single time? (i.e. - why does the computer only reset some of the time?) Also, it seems to me that any loss of continuity like that would probably cause the bike to shut off instantly? (whereas now, it actually just slowly loses RPMs and sputters out when it stalls).

I think I've informed you guys of everything I know as of right now. I sure do appreciate the support!

CHEERS,
Jon W.

 

When your checking the connectors pull on each wire. I'm wondering if a wire is loose or some obstruction in a connector. I think with the spuratic nature of your symptoms something is coming loose. Check the ignition wiring too.

 

If your meter is reasonably calibrated, yes it makes a difference.
100% Charged: 12.7V
75% Charged: 12.5V
65% Charged: 12.4V
50% Charged: 12.3V
25% Charged: 12.0V
0% Charged: 11.7V

You're only dealing with 1V from fully charged to discharged. A good battery will read 12.7V 4 hours after being taken off charge. If your battery is really at 12.3V after being charged then sulfation has already begun. Replacement is typically recommended if it's below 12.5V.

You may have replaced your bad battery with another bad battery. If all your other batteries read 12.7 and this new one reads 12.3, then send it back.

If the problem is in the computer itself, heat could be the cause. Stuff expands when it heats up. A bad solder joint on a board is not easy to find when you're looking at wire harness connectors and batteries. I prefer stuff to blow up when it's failing. It's easier to find the problem. This kind of intermittent stuff will drive you nuts. A failing battery will draw high charge current for extended amounts of time. Longer than what the KLX is designed to do. Not sure what the bike will do when the charging system is pushed to the limits.

 

How much time/miles between the hard Moab drop/repair and onset of this problem?

Is the instrument cluster resetting even w/ the new battery?

Have you confirmed no spark when the bike dies/wont start?


.

 

If the dash still resets at all with the new battery that is where I'd start as it will only do this when it has lost all power.

 

DYNOBOB: I only took one dualsport ride and a couple of short road rides in between the star gear repair and the onset of current symptoms. No additional crashes or anything on the dirt (or street). It's hard to remember at this point, but I actually don't think the computer has ever reset while using the new battery. In general, it seemed like the computer would only reset when the bike would stall after running for awhile... now, even if I happen to get it started at all (whether that's with a moto battery, car battery, or jumper box), it will only run for a few seconds before stalling, but in general I have not seen the computer reset during stalling for several days.

I was testing electrical connections to the CDI last night and was unable to find anything that was conclusively screwed up. I did find it to be interesting though that the bike would still try to crank and turn itself over even when all of the wires to the computer were unplugged... I would have guessed that would disable everything. Obviously, it never actually started though, just like for the past several days... but if it weren't for my current problem, would the bike actually run ok with the CDI unplugged?

If I can get the bike to turn over and run for a minute then stall while the computer is unplugged, I feel like that would be a good indicator that it's NOT the computer. Similarly, I have gotten the bike to turn over and run a few seconds while the alternator harness is unplugged, in order to do the service manual tests on the rotor and stator (unfortunately it never runs long enough for me to be able to actually do those tests). Even with the alternator unplugged, the bikes stalls in exactly the same way... seems to me that would strongly suggest that the alternator is not part of the problem, no?

 

You don't have an electrical connection problem.
It starts runs a bit, then dies. This is repeatable with the same approximate time? If yes, no intermittant elec connection is going to break at the same time everytime.
Your battery replacement fixed the computer restart. Quite worring about the connections.
My $1.01.
Have you ever check the spark after it dies? Did you replace the plug?
Have you ever checked that fuel is getting to the carb after it dies?

 

durielk: I agree with you very much at this point. All along I've been torn over whether it was electrical or fuel system rated. Given the odd reseting of the computer that happened a lot of the time, electrical was where I decided to start the diagnostics... but, given where I'm at with it now, I need to rip the carb out and check for fuel flow in, out (and out of the tank), check all the jets are clear, etc, etc. Too bad that pulling the carb out of these KLX's is about a 48hr job!!! (just kidding, but it's a bitch)

I have NOT replaced the plug yet, but intend to do so. I have, however, verified that I am getting a spark within all ranges I've been able to test.

I'll report back once I've done some fuel system diagnostics...