I have an 02 recon es 250 that i picked up a k&n filter and dynojet jet kit for. Put the filter on and seemed to run fine what little I ran it. Put the jet kit on and it runs awful. Tried different jets that came with it, no better. Went back to stock needle and jet, still no better. With any of the jets and needles in it, it ran alot better with the airbox lid removed, put it back on and runs awful again. I'm new to working on these things, i know i'm missing something that would be obvios to a seasoned person.

Any help would be greatly appreciated.

 

make sure the drain tube from the bowl is hanging straight down and not clogged.

 

you need to put a pipe on it to use the jet kit. putting an air filter on wont help because the exhaust is still restricting the air flow, causing no need to re-jet. Save the jet kit until you pipe it, then use it.

 

I put the stock jet and needle back in and still have the same problem. I even put the stock air filter on. I know i'm over looking something simple here. First time working on one of these so i'm not too familiar with them.

 

If your choke plunger or cable is binding or sticking inside the carb it can cause a rough idle and make it run poorly.

 

I'm about 99% sure its the drain to the bowl. Make sure the tube hangs straight down .Loosen the valve and make sure it drains.

 

loosen what drain? Your talking about the small hose directly on the bottom of the float bowl? I haven't had a chance to get out the the recon to check the hose yet...

 

yeh thats the one.

 

Why would a clogged carb drain cause it to run poorly? I'm just curious because myself and many I know keep ours plugged for swamp riding and deep water crossings.

 

The float and the level of gas in the carb causes it. The drain or overflow keeps the float working right. Gas should pour out of the drain when you tilt the fourwheeler on its back rack if it is working right.