New to the site. I bought a 2006 klx 250, (850 miles) its all stock and I was needing to know some easy modifications I could do to increase performance. It runs great but I would like more. I read something about changing the jets, exhaust, and air filter, but I didn't get the details. Can anyone give me some good advice? Also, anything else I need to know.

 

Ok here it goes.. The KLX250's are restricted due to laws... And these restrictions can be taken off...

The first thing you should do is get a Jet Kit (They are an assortment of Carburetor Main Jets and in case you get a Dynojet Jet kit you get a drill bit to enlarge the slide vent hole and a adjustable needle too).. The stock main Jet on your bike is a #118 and the stock needle cannot be adjusted as easy as a DYNOJET needle..

You should first get the Jet Kit because from the factory the bike is lean..

You Should also get an After Market Exhaust like a FMF,HMF or Muzzys.. Rejet is neccassary after a exhaust too..

And the Air box on our bikes has a lid which you can take off, but if you take it off you need to give more fuel in because taking it off gives more air.. Some people take off the whole lid and some people just take off the snorkle.. Some people also replace the snorkle with a Kawasaki KDX snorkle for better air flow..

A good air filter is a TWIN AIR FILTER or Uni..

So whatever you do ReJetting is a MusT!

More Air In - More Fuel - More air Out = Performance!

 

What he said.

 

Try search button tons to read.

 

See these threads:

https://www.kawasakiforums.com/forum...ead.php?t=5090
https://www.kawasakiforums.com/forum...ead.php?t=2041

And on ThumperTalk:
http://www.thumpertalk.com/forum/arc.../t-323684.html

And on Adventure Rider:
http://www.advrider.com/forums/showthread.php?t=128219

In addition to the above suggestions, with the aftermarket exhaust you may want to remove the Clean Air System (aka "air injection system" or "air valve"). Otherwise the exhaust runs hotter 'n hell and the bike backfires on decel. There's a step-by-step with photos posted somewhere, but darned if I can find it. The CAS is a hose that connects to the front of the engine (near the exhaust port if I remember correctly) into a vacuum switch that has a small vac line to the carb and a larger hose going to the airbox. Remove the entire thing and cap off all the openings (I used rubber caps and high-temp RTV I picked up at the local NAPA store).

I also saw a reference to going to an older computer (pre-2001) in one of the threads - looks interesting.

 

The second sticky thread on this forum has everything you'll need.