A KLX 250S with 300 cylinder, pipe, proper jetting, opened airbox, & quick turn throttle is leaps & bounds ahead of a stock 250S. Have fun.

COntact Moto-Pro & get some springs to suit your weight.

 

& drop your gearing too. If you never ride on the street there is no reason for the stock 250S cogs.

 

..............but still nowhere near close to a KDX 200/220 power. even with all of those mods, the KLX is virtually still a dog to someone who just came off a 2-stroke.

 

run it into the ground.....lots of plated 2-smoke ktms out there.

 

Or put the kdx motor in a klx frame

I wonder if the klx 6-speed tranny could bolt to a kdx motor. That would be cool.

 

Beside the point. The poster I am responding to (captaintrps) has a KLX now not a KDX anymore so he knows better than you what the difference is. I am simply letting him know where to go from here. But thanks for ponting out the obvious though.

 

oh I apologize. I didn't mean to ruin your expertise ladenpost regarding yourhighly intelligent info. about how to pipe, jet, and re-gear a KLX to increase it's off-road capability. I mean, jeesh, why were you withholding that type of advice all this time? That stuff there will totally change the way all KLX's are modded and thus thought of regarding their monster power capabilities with just your mentioned mods. It amazes me that no one had ever thought of adding an exhaust, rejetting a carb, and changing a sprocket to get a bike to run better. You're an absolute genius.

 

Thank you, glad you are now realizing it.

 

I appreciate it KLXer, this site's been invaluable for the information and input from you guys who've been there/done that. I couldn't plate my KDX, but I almost bought one that was, but it was ragged from enduro's...and now I ride with my wife so running from the rangers isn't an option anymore. Coming off of a KDX, this is my to do list for the winter. I'll see where I'm at in the spring:

-blinkers gone
-mirrors gone
-chain guard, rear foot pegs, seat strap gone, lol.
-smog stuff gone
-kickstand safety thing gone/bypassed
-black rear fender thing gone
-stock tail light gone, in lieu of the small one from Baja Designs
-front headlight gone, need a smaller/lighter replacement
-Bill Blue modified pumper carb with motion pro throttle
-Over bore kit, probably in the spring...not sure which one to get.
-pro taper se cr high bend bars
-13T front sprocket
-45T rear, alloy
-lighter chain
-kickstand gone
-excel rims, get rid of the heavy stock ones
-probably front fork springs, but I'll assess that in the spring.
-cut the rear fender area of the frame off
-four stroke works exhaust or something...
-something to make shifting more smooth, or maybe I just need to break it in more? I'm switching to Amsoil, see how that works out.
-something to make the front brake work better, or again maybe I just need to break it in more.
-clarke tank
-put some stickers on it - this alone should be good for 5+ HP. :-)
-Tires!

That's my starting point anyway. There's a dyno shop on my way to work, I was going to stop in and see what they have to offer.