Hello,

I recently purchased a klx250sf as my first bike. After putting a hundred miles on it I figured I would clean the carb not knowing what condition it was in from the PO. I took it out and it was clean as a whistle, after putting everything back I can not get the bike started.

What I know right now:
The bike is getting spark.
There is gas getting to the carb.
Gas will drain when drain screw is opened.

I am new to doing any kind of mechanical work, but it seems as though the cylinder isn't getting gas. I am not sure if it is not pulling gas due to some air leak? I checked all the connections and everything is tight and the carb is seated firmly in the rubber boots. I am not sure what to check or do next.

Thank you for any suggestions.

 

Check the slide. Might be stuck down. Did you remove the top of carb too.

Also check for air obstructions ( like stuffing a paper towel in the intake and forgetting about it). That will do it. Ask me how I know....

 

Paper towel in the intake?...What an idiot! Everyone knows you should be using a white athletic sock. You don't have to ask me...I know.

OP, I take it from your description that the bike has not even fired at all. Usually even a stuck slide or plugged pilot jet will allow the bike to fire and maybe even idle using the choke on a cold engine. You have spark, you have air...barring the possible obstruction in the airbox/intake mentioned...so you should fire with some fuel. While you're getting some fuel to run out of the drain spigot, I wonder of the fuel level got screwed up...bent the float somehow...during your inspection to not allow the pilot or choke circuit to pick up fuel.

Unless the plug is fouled...doubtful...the choke will at least usually allow the engine to fire.

 

If you haven't had any luck yet, I may have just the solution you need. Turn the petcock to the on Position, or reserve if you're low on gas, and don't do anything else for 10-15 seconds just to be sure that gas is getting into the float bowl and filling it up. Then turn the bike on, pull the choke all the way out, flip the run switch to on, pull clutch, and try to start it. It will take a few cycles to get the gas into the engine to let it fire, but it should at least sputter a bit. If not, my friend showed me a trick with these finicky KLXs. While it's turning over, give it a quick thwack of throttle, not full throttle, don't hold it open, just a quick turn while holding the start button. Usually works best without the choke though.

If none of this works and it's just cranking over and over to no avail, I hope you have a nice long driveway or open area to run. Concrete is better, but grass works too. As a last resort, pull the choke with the bike on and in gear. Ignore the start button, but pull the clutch and run. Once you hit about 6 or 7mph, jump on the bike and right when your weight hits, pop the clutch. It might work the first time, it might not, and you may have to give it a bit of gas. If this works, that means that your battery is dying, trust me.

Hope this works for you. Btw, what all has been done to the bike, or is it all stock?