Hi everyone i have a 2013 klx250s that was running great until a few days ago.. Now the bike is boggin when trying to increase speed at high rpms
Bike starts fine and runs good til you open throttle to go faster
Before this problem i was getting 93 mph top speed(speedometer reading) now it barely passes 70
Also second problem bike backfires/pops when let off throttle?

Anyone have any idea what it is or what it may be?
I drained gas and refilled, changed spark plug, did oil change, oil filter, dropped carb needle down a notch

What else can i do for either of these issues?

Thanks for any advice!

 

If nothing changed from running great to bogging, you have to look for a cause like crud in the carb blocking the main jet or similar cause. It won't magically change in jetting. There is something doing it that wasn't there before. A fill up before it started, possible contaminated gas? I don't have any real answers. Just trying to stir some thought.

 

Thanks for quick reply! I drained the gas out twice already and refilled fresh gas wasnt that.. I guess cleaning carb will be next step? I only ride on road never went off road on this bike yet. Checking the main jet? How should can i do that? Im not familiar with carb cleaning!

 

is the air cleaner dirty/clogged??

 

No it is not dirty or clogged at all!

 

Your gonna have to check your fuel filter - it's in the carb fuel line nipple.. Cross your fingers that it is half full of junk..

 

99% of the time, it will be starving for fuel or air. I'd recheck everything. Is this bike most ridden on or off road? If off road, just do yourself right and clean the air filter. You can't always see super fine dust/dirt that will restrict enough air flow at high speed. These bikes really pull a large volume of air at the top like your describing. Also takes a little piece of grit in your carb to restrict a jet. Most likely your main if at WOT. Any chance you nocked the flote level out of wack? If the bowl isn't filling up fast enough to supply fuel, that will also cause the same problem. Also, make sure your tank is venting.

 

Ok, so the first time I read your post real fast. Now I see you ride street, and didn't have carb apart yet. I wouldn't change jetting before fiding the problem. Don't move the needle location yet. I'd put that back to where it was, then do what I said in above post. You may just have a piece of dirt or something restricting your main jet. You did say its doing this with throttle close to wide open, correct?

 

So, what kind of threat will get you to check your fuel filter - buying your mom-in-law a one-way ticket to your house?

 

For some that might be enough to trade the KLX off for a KTM690!