Hello, I own a 2007 KLX250h and am having problems. I let the bike sit for 8 months, took the carb apart, cleaned everything out, both jets, used compressed air and carb clean, replace the battery and spark plug. the bike now idles perfectly until it comes time to ride it. The bike runs fine or a minute and then seems to lose power and tries to stall.

if not a float level or jet problem
worn carby
ebay sellers have them

it is a garantee that the main jet is stoped up with that grayish dried gas minerals..this not in the main jet valve you can remove,but actually in the bore on the carb body... you can try to use torch tip cleaner to open the hole ...hope you the best ....it is a very hard substance...someone tried starting the bike after being set up for a while without removing carb and cleaning first.....sincerely;R.B.V.

clogged jet

I assume this is a curbreted model. Most likely the pilot jet is plugged. Pull the carburetor and clean the jets and passages with the proper tools and cleaners. Do not use wire to clean the jets, use an appropriate carb cleaner or the proper jet drills if you have/know how to use them.

float stuck

Does it have fuel filter that you can replace?

The pilot jets are still gummed up. This jet controls the idle port and usually gets overlooked. To clean it the jet must be removed along and the adjusting screw as well. The circuit must be cleared of gum. For each individual carb, when removing the jet and the adjuster, count the turns then remount that number of turns. Now turn the adjuster screw 1/4 turn counter clockwise.

I had the same problem, Turns out that my shims were finished, replace the chims and check clearences.

I would take the carb off and clean the jets. I had a bike that if i didnt ad stabil to it, the gas would varnish in just about a month. It also depends on what kind of gas you put in there and if you fill the tank up so condensation doesnt get in there.

I'm new to the site and new to carbs. I bought a bike last week that had been sitting in a barn for a couple years the engine hadn't been running in over a year. I was able to get it running the first day after cleaning out the field mouse home occupying the air filter chamber and swapping the old gas for new gas. The bike ran and idled fine but the left carb (dual carb setup Keihin) poured gas from the tube coming out the bottom. I did some research and found out the floats may be stuck. I went ahead and ordered new floats and float bowl gaskets. I took the carbs apart apart as much as I could, using Berryman parts cleaner to soak all the metal parts I could get off. I put everything back together and put the new floats in yesterday. I started the engine and not only is the gas is still pouring out the bottom of the left carb, but now the bike is idleing very fast. The idle adjustment is backed out completely. When putting the carbs back together, I screwed all the jets back in all the way. I screwed in the Pilot Air screw, the one with the spring, all the way in, then backed it out 1 1/2 turns. Not sure if this has anything to do with the idle. As far as the floats go, does it sound like I need to replace the float valves too? ,The seats on the jets, or the o-rings on the needle valves that the floats control are probably leaking.,,,