Hello everyone, I hope someone can help me. I'm having idling issues with my 1995 KLX 250R. Let me fill you in on what's been done so far.

I have already had my valves rebuilt and replaced my cam chain to factory specs. The engine has good compression and I've cleaned the carb twice now. I've also checked for any water in the fuel system, and there is none. The idle/fuel mixture screw is 1.5 turns out and the spark plug looks good.

O.K..... now for the problem: When I ride the bike off road on single track after half a kilometer or so, the bike no longer wants to idle for me correctly. I will let the bike cool down for about 10 minutes, then restart it. At that time, it idles perfectly, in fact it purrs like a kitten. If I take it for a nice easy road ride without any major bumps or fast moves, the bike continues to run perfectly. I notice the idle issue is only when I take it off roading and the fuel sloshes around in the bike and the engine gets hot.. What's the deal here, I can't seem to figure it out. Even on cold starts in the morning, it idles fine with the choke and once the engine heats up, and I turn the choke off, it idles perfectly. Even when this idle issue arises, the bike still has plenty of power riding it around....I just can't let the bike stop or it stalls..

Please help

KLX Fan

 

Check your fuel tank ventilation tubes. Or if you have a ventilated gas cap, check that. Not sure about the 95. If you are 100% sure about the valve clearances, this is the only remedy I can think of assuming you thoroughly went through everything else in your original post.

 

I do have a ventilated fuel cap. Its like an older motocross cap with the breather tube out the top. How do I check to see if its working correctly? Are you suggesting the fuel is not flowing into the cab correctly?

KLX Fan

 

Yeah, there's a chance that it's not. Especially if the problem only occurs when you are in the midst of riding while the fuel is splashing around in the tank. Does it happen when the tank is completely full? I'm not sure how to check the ventilated gas cap, only had ventilated tubes on my bikes.

 

Ya it does it at any level of fuel in the tank!

Wonder if it has anything to do with electrical? Coil over heating? Intermittent electrical connections. Things get hot and electrical resistance ramps up? hmmm.........

KLX Fan

 

Pull out the voltage meter and do some testing. Check your plug and plug wire. Check the CDI.

 

Any suggestions on how to test out that stuff with a voltage meter?

KLX Fan

 

Honestly, I have no idea. I know how to use a voltage meter for basic things like testing continuity and voltage but you'll have to see if you can find the specs for the CDI under load and etc. As for the plug and wire, check to see that the wires aren't frayed and that the connection is solid between the plug wire and where it connects to the slip on rubber piece that goes over the plug. My old plug wire on my 06 had to be replaced because I could actually pull it apart because the wire had become frayed and was only touching but not connected.

 

First, make sure your air filter is clean and the carb boots are tight.

The three things I suspect first are fuel float/needle seat/bowl fuel height, and aging vacuum lines/caps, and venting...both fuel tank and carb vent.

It's simple to check the height of the fuel in the bowl with a piece of clear tubing. It's also simple to replace any vacuum hoses/caps. Make sure your tank vents are working and on correctly, and that your carb vent line that originally dumps out to the ground near the rear shock is completely clear of any obstructions (including spiders/webs/mud, etc.).

 

Another thing to check on a bike as old as yours is fuel delivery. Make sure the little filter sock in the tank on the end of the fuel petcock isn't clogging to some degree. Do you run any external fuel filter in the fuel line?