Hi, I have a KLX 250 07 model and I have had it to 2 mechanics and I have spent probably 50 hours on it and still cannot get it going.
Everytime I get it back from the mechanic they say low compression and weak spark but are not really sure why it will not run. The compression is 120 psi dry and 150 psi with a bit of oil squirted in the pot, the manual says it can get to as low as 80 psi so I would rule out compression. The spark is a worry as with a new spark plug in the spark is weak and seems to be erratic, the CDI has been changed as the other was no good. The carb has been pulled apart and seems ok, pulled the barrel off to check the piston and rings seems like new. Checked that cam timing was OK. Have squirted Aerostart into air intake and it will not even pop when starting. I am at a loss where to go from here, any rational ideas would be welcome.
Is it possible to wire up another CDI of another bike to check as CDI are about 600 bucks.

 

Have you replaced the spark plug boot and wire?
Start with the wire, it's cheap. A good moto shop will sell it by the foot. Then try a new boot.
After that, it's time to get out the multi-meter and test some other components for continuity, resistance, and the like. Or start spending money replacing things down the line. I have a bike that has two of everything electrical and nothing worked, the problem was a 10¢ resistor that was missing. Not saying that is the problem just...
Start simple. Plug wire and boot connections.
Nothing will stump most mechanics(even good ones) like electrical problems. DAMHIK...2/5 of my bikes are haunted by electrical problems.

 

yeah maybe it is something small, the mechanics these days are not interested in anything that is hard to find.

 

Have you contacted a Kawasaki dealer specifically? I know it may be expensive by the hour, but the dealership should have best knowledge to troubleshoot the ignition system. When I worked at a Honda dealership I saw a few riders buy virtually every electrical part spending hundreds, but not wanting to spend an hour of shop time to try to see if the problem could be found by a trained Kaw mechanic. To save about $50 at that time, he blew a few hundred on coil, cdi, and other stuff, none of which did the job and no electrical parts are returnable.

I'm not saying every Kaw dealership mechanic is super-skillful, just that if you talk with whatever shops might be available you can learn something about their background and skills, then decide if you want to work with one of them. They also have access to Kawasaki service support, plus possible past experience with what may be the problem. They also may have a bike that they can swap parts with to see. If they have a used model using the same parts the guys where I worked would swap parts to see if they could discover the problem that way. Never used customer bikes, but definitely our own. Swap black box, swap coil, whatever.

Set the limit on time and money - like 1 hour at whatever price - then they contact you with results at that point. A shop with a good trained mechanic can do a good job. I worked with a few mechanics who were great. One found an electronic issue in a Honda that even the support could not solve - with the service rep coming in to work on it. Those guys had a reputation for their skills.

 

Maybe it's something really simple like bad gas in the bowl. Try draining the carb bowl, let in fresh gas and see if it fires up. Just sayin.

 

I wish I could help but I'm not a plethora of KLX info, sorry. But being a mechanic I know I could fix it if it were infant of me. All I could say is make sure all the basics are good. Check all power and ground connections, check any fuses or relay contacts for corrosion and so on. Like said before, check the ignition cable. Remember a typical digital multi meter with a 9V battery only loads circuits to 1.5 volts, so if your ohm testing stuff you might not find any issues. Where as when the circuit is "active" the problem might be present. Also, does the engine have good cranking speed? That might effect its starting ability too.

 

I'd say look over the entire harness too, make sure nothing is kinked or rubbed through. Sometimes wires will short to chassis or another wire and not blow fuses, but they'll draw on each other and pull down other circuits.

 

Lepo, where are you located? Maybe you can find another KLX owner nearby?
I blew my CDI. Wasn't positive that was the issue, so I took it to another KLX owner and put my CDI on her bike which confirmed her's wouldn't start with my CDI. Found one on ebay for around a hundred.

Good suggestions above. I'll also throw out a possible stator issue.

 

Hi thanks for all the replys, the last mechanic was the local Kawasaki dealer as I thought that they should be able to find the problem but they also said they did not know maybe a combination of things. For some reason it is hard to find another CDI for this bike and really do not want to spend 600 on new if that is not the problem. I think I will just start at the beginning and check everything again, before it burn the bike. I am in Perth Western Australia.

 

When you say you are not happy with spark if you take the plug out and hold against engine case are you getting a consistent spark, there is a 100ohm resistor in the ignition if that is not seen then you won't get a spark , I cut my damaged ignition out the circuit but had to add in the resistor to get bike to fire. Have you had an auto electrician check the ignition circuit and can you get the plug wet with fuel so you know that fuel is getting there