Hey Guys and Gals,
Just bought my KLX250s on Friday and love it!
However, I'm in need for more power (low end mostly but would also like mid and high too).
Does anyone have a detailed list of modifications and approx. power enhancements (HP) for each improvement?
Thanks,
Brent R.

 

search here and you will find.
almost everything for the klx300r will fit.
order n1tc adjustable needle from klx300, bigger main jet, drill slide vent,etc
only a full exhuast from a 300 will fit. the headers are different so slip on wont work.
a 13 tooth countershaft sprocket will help low end. but not the same as the 300. the one i got was for a honda xr650L
a intake snorkle from a kdx200 will flow more air

all of this will make a much improved difference.

check the "sticky" posts at the top of the forum for more info

 

klxstiffler has summarized most of the mods that make the most difference. The most economical for the performance, I thought, was the airbox snorkle, carb jetting & adjustment, and drilling the stock exhaust first baffle to 1/2" - only about $50 or so, depending on where you get your parts. But if you really want the bike to sing, put on an aftermarket exhaust or fit a KLX300 stock exhaust. And if that's not enough, go for the 300cc big bore upgrade which will increase your displacement by 20%. That makes a very noticable difference especially with raw torque all across the RPM range.

 

I've done these modifications they work good.
You will smile.

16009-1912 Kawi Needle-Jet, N1TC
92037-1401 Kawi Clamp, Jet Needle
92143-1667 Kawi Collar
Needle clip slot 2 down from the top
92063-1069 Kawi Main Jet #125 or 92063-1074 Kawi Main Jet #128
92064-1108 pilot jet #40 Air screw at 2 turns out to start
drill the slide vent to 7/64ths

Airbox snorkel (14073-1577) high flow unit

open up the crank case vent hole in the airbox

10-4313-K250 big gun evo x exhaust system


air valve removal ( Air Injection System ): This won't do squat for performance but it will lower exhaust temp significantly and cleans up the under-tank area.
just plug:
the hole in the airbox,
the vacuum port on the carb,
and the intake to the reed valve on the front left side of the head
( I took it off and made a cover to replace the reed and cover )



KLX 300 Kit

1 x 11005-1983 - CYLINDER-ENGINE Price: $309.93
1 x 13002-1109 - PIN-PISTON Price: $9.63
1 x 13008-1071 - RING-SET-PISTON,STD Price: $36.66
2 x 92033-1054 - RING-SNAP Price: $0.84
1 x 11004-1314 - GASKET-HEAD Price: $37.31
1 x 11060-1740 - GASKET,CYLINDER BASE Price: $5.16
1 x 13001-1463 - PISTON-ENGINE Price: $62.64


99924-1165-03-----Service Manual KLX250D
99924-1240-55-----S/M Supplement KLX250H
________
Vaporizer

 

Hey Ted,

Are the part #'s you have listed for the klx300 kit, kawasaki part #'s? Where did you purchase your kit from? I have called all my local kawasaki dealers and they cant find it, or dont know what they are looking for. Makes me kinda worried to have them install it once I do get my hands on one.

Thanks,
Steve

 

Those are Kawasaki part numbers - just cut and paste them into RonAyers.com parts search box. I had my parts in about a week and did my own install. I posted about it with lots of pictures. Search this forum for it - it was just a few weeks ago.

 

Thanks for the info Nobreaks. I did read your install thread, there is lots of good detailed info on how to install it. However, I will not be taking on your endeavor, I'm too much of a wimp. I just worry that my kawasaki dealer could not find the kit and Im going trust them to install it correctly once i get it from Ron. I just hope its worth it.

Steve

 

Here are the most common I have read about.

Muzzy full exhaust or you can drill a hole in the stock exhaust, there are several posts on how to do that.
#125 main jet (Size depends on several factors, see posting on jetting)
pre-'96 KLX300 needle (N1TC)
pilot air screw backed out to 2.5 turns
Slide vent drilled to 7/64th
Airbox crankcase vent restriction removed
KDX200 snorkle (hi-flow)
13t counter shaft sprocket (14t is stock)

The links below show the part#'s, how to remove the carb, how to install the carb parts, and Kawasaki web site for diagrams of carb, ect..

http://www.hmfengineering.com/forums...ead.php?t=1617
https://www.kawasakiforums.com/m_17800/tm.htm
https://www.kawasakiforums.com/m_34306/tm.htm
http://www.kawasaki.com/Default.asp?...D=2&intParts=1

 

Get all the parts.
Bring it to me I'll put it together for you.
Bremerton, WA

I purchased the Kawasaki parts at Cliffs Cycle Center in Bremerton.

I purchased the big gun evo x exhaust system From
Pro-Flo
http://pro-flo.com/index.html#BUTTONS
http://www.pro-flo.com/big_gun_kawas...systems_II.htm
11-10-K31C (94-03) KLX250/300 Complete System 384.95
( It took me a long time to get it, things may be different now )


Big Gun part #
10-4313-K250 big gun evo x exhaust system

All Kawasaki part #'s
KLX 300 Kit

1 x 11005-1983 - CYLINDER-ENGINE Price: $309.93
1 x 13002-1109 - PIN-PISTON Price: $9.63
1 x 13008-1071 - RING-SET-PISTON,STD Price: $36.66
2 x 92033-1054 - RING-SNAP Price: $0.84
1 x 11004-1314 - GASKET-HEAD Price: $37.31
1 x 11060-1740 - GASKET,CYLINDER BASE Price: $5.16
1 x 13001-1463 - PISTON-ENGINE Price: $62.64


99924-1165-03-----Service Manual KLX250D
99924-1240-55-----S/M Supplement KLX250H

16009-1912 Kawi Needle-Jet, N1TC
92037-1401 Kawi Clamp, Jet Needle
92143-1667 Kawi Collar
Needle clip slot 2 down from the top
92063-1069 Kawi Main Jet #125 or 92063-1074 Kawi Main Jet #128
92064-1108 pilot jet #40 Air screw at 2 turns out to start

Airbox snorkel (14073-1577) high flow unit
All Kawasaki part #'s
________
PAXIL LAWYERS

 

ted....after all the work here with the front wheel come up 1st or 2nd with just a twist of the throttle?? i thought long but maybe not hard enough before purchasing this or a DRZ400 and went with the KLX dye to some notes of the DRZ400 being cumbersome and hard to handle due to size/weight when off-roading but the lack of power the KLX 250 has dissappoints me