I have a 2002 KX250 and out of the box it's not bad for trails but it wants to stall at slow speeds and can be a handful on steep hills.The gearbox on the 02 kawi is very wide and lends itself well to trail riding with a few mods.I put a Clarke 3.3 gal tank (nice look and fit) on it.Steahly 11oz flywheel weight.V-Force reed cage,went to a 48T from the stock 49T rear sprocket.FMF Fatty pipe and a Pro Circuit sparky.Power delivery is much smoother now and doesn't want to stall in the tight stuff and has really good top speed as well especially for an MX bike.Rear shock in my opinion is excellant as is.The forks are stiff for trails and I run the clickers all the way out.Even with this setup it still runs great on the track.The only thing I might change back for the track would be the gas tank.Tight corners are much easier when you can scooch up close.Even with the clickers all the way out in front the forks handle the track well and I only bottomed them once but it was a real bad landing but I stayed on the bike.
Yea, all the stuff stated above sounds like good stuff. I think you'll find the most important adjustments would be the gearing, I'd go a few teeth on the back, and a flywheel weight. After that, get your jetting and suspension dialed in, and HAVE FUN!
heres the formula:
52 tooth rear sproket
eric goor head work "mo betta everwhere"
mid to heavy flywheel weight
boyesen carbon fiber reeds, NO RAD VALVE!!!
adjust jetting to compensate
the bike will not have the HIT it had before, so initial SHOCK VALUE to scare your friends is decreased, UPSIDE,,, you will fly through the woods with little to no stalling and you will last twice as long,,,at least this combo worked for me for years on a 99 kx 250.....good luck!!
1. What is a flywheel? What does the weight mean? What is the purpose of the weight change?
2. What is a reed cage?
The flywheel is attached to the engine crank,it's job is to keep the engine running smoothly.A light flywheel will allow the engine to rev faster and give it burst speed like you would use in motocross to exit corners and clear jumps.When you let off the gas the engine will quickly lose power and may stall without quick and effective use of the clutch.A heavy flywheel will keep the engine running at low speeds without stalling and it will also make the engine not rev so fast making it easier to handle in slow terrain.The Steahly flywheel weight comes in 7,9,11,13 oz's. for the 02 KX250.It is a bolt on item that attaches directly to the existing flywheel to increase the weight and is easily removed.
The reed cage is an assembly that directs the air/fuel mixture into the cylinder.It's located between the carburator and the engine cylinder .I can't describe exactly how it works but the flow change will also change the power output of the bike.The Delta Force gives the bike more low to mid range power with a little more on top but I don't have to use as much throttle to get the meat of the powerband.The installation is quick and easy on the KX and replaces the original reed cage leaving the stock one intact.
I'm still using the stock carburator jets and needle position even with the new exhaust system and reed cage.The bike runs very clean and sputter free.
I don't think having your engine ported is a good idea at this point.The change would a permanent one and if you don't like it your stuck unless you buy a new cylinder.Riders with a lot of experience know exactly how they want their bikes to perform so porting is a way to achieve their goal.
The type of trails you ride will determine what needs to be done to the bike. To some people, trails are 4ft wide, and can be ridden in 3rd gear or higher. For those trails, the KX will work very well stock. To me, trails are barely wide enough to ride through. Mostly 1st gear, with an occasional shift to 2nd. For that, you'd likely want to ADD 1-2 teeth to the rear sprocket to bring first gear down. Possibly have some suspension work done to soak up rocks, roots, and logs if you have that sort of terrain where you ride. Handguards are a good idea to save your hands, and your levers. The other mods are optional IMO.