Could it be a cut wire that is rubbing against metal and shorting out? When you buy used you never know what the previous owner did to the bike. I'd rip every piece of plastic off and go through it wire-by-wire. Didn't the seller acknowledge having similar problems?

 

Easy test is try to run it with shots of starter fluid. Pull the airfilter.


Bike will not run w/o CDI plugged in.


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Brieninsac: No problems at all from the previous owner... bought the bike from him back in '10 with only 500 street miles on it. Never had any issues like this before. The only electrical thing that I screwed with really at all was the kickstand switch removal, which I know isn't causing the issue (I've double/triple/quadrupel checked that my solder and cap job on the two joined wires is still intact (and not contacting anything else).

DYNOBOB: I still have not tried your starter fluid suggestion... but probably will soon if the next few tests I'm doing don't give me any results.

I'm determined to solve this thing and let everyone know what the hell it was!

 

Your dash reset because it lost power when you tried to crank it over while the battery was in a bad state of charge. Mine did that too.
The not running sounds like a jet or two is clogged.
Will it run WOT? On choke? If yes to both then it's most likely a clogged main jet.
The only problem I've had with my bike was due to clogged jets. My money is on the fuel part of the fuel/spark/air equation. Either a clogged jet or an improper float height(check first before opening the carb and going fishing for other stuff).

 

PS - DYNOBOB, you said it won't run with the CDI unplugged... but does it still make sense that it would at least try to crank over?

I could answer that question in a few minutes by studying the wiring schematics, but I'm getting tired of those

 

Well... there was nothing obvious wrong with the carb. I basically gutted the whole thing in the end, and there wasn't a single speck of dust anywhere, not in the fuel filter, jets, or anywhere I could see. I haven't reinstalled the carb to try to start it yet, however, because it seems obvious that nothing is wrong in the carb.

I guess next I'll pop in a new plug and test the venting and drainage from the gas tank (any good ideas on how to do that with the stock KLX tank?) If it doesn't fire up after that, maybe some shots starter fluid into the carb... but other than that I'm fresh out of ideas.

I've loved my KLX immensely, but I've had so many problems with it during the course of my ownership... far more problems than I should be experiencing with a good bike like this. If this crap keeps up I'm buying a KTM!

 

did you pull the pilot jet and clean it while you had the carb out?

 

It will crank w/o CDI.


The reason I keep suggesting starter fluid is it will answer instantly if the problem is fuel delivery or spark (assuming you don't have a wet plug, pull it and make sure). It cuts down on the tail chasing...


You'll figure it out. Enjoy the relative simplicity/reliability of the KLX. If you get a euro bike you'd better plumb in a fuel pres gauge and led indicating power to the pump.





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UPDATE:
I haven't had a chance to work on the bike for the past few days, but started checking out the fuel tank/lines tonight. Also, I did verify that I have a good spark (at least while cranking). The first major thing I noticed was that the gas would flow fine out of the tank with the petcock set to "reserve", but when I flipped the petcock to the FUEL position, the gas flows with very much resistance... more than a trickle, but not nearly the same flow as from the "reserve" position. I basically checked every single last line coming to and from the tank, disassembled the entire petcock, and examined the tank fuel filters. I found no blockage whatsoever anywhere except in one of the two longest tank lines (the tan ones)... there was a tiny little dense spiderweb of some sort in there... I blew it out and cleaned it up. It did give some resistance when I blew it out, so I can definitely see that having been a big problem. I can't tell from anywhere within the service manual dwgs... but are those vent lines? Air or gas or what?

Next, I happened to notice that there was no liquid down in the little collector in line with the air cleaner drainage line... I usually notice that there is liquid in there, but had never realized until now that you are actually supposed to purge that excess fluid out every now and then by pulling the plug at the bottom of the hose. Well.. that plug is now missing, along with the clamp collar that used to seal around the hose. Can't tell from the manual either, but would keeping that drain open pose any risk other than just getting some dripped air filter oil on your tires? If it depends on some kind of positive or negative pressure in there then maybe thats an issue too...

Gonna use some fuel tank cleaning solvent and then put everything back together and maybe try some starter fluid... what do you guys think?

 

I put a vinyl cap on that collector bottle after mine ripped off during an off-road excursion. The white one(from Home Depot) is the correct size to fit on the bottle.
They also have all the sizes required to do the free mods capping of lines, just add sealer, if you haven't already.