There's no restrictors in the carb-airbox duct, or carb-reedvalve manifold. 15/48t is the best gearing compromise however! If you tune the engine closer to 25bhp at the wheel then it can pull 16/50t gearing to give almost 90mph, but with less acceleration. However you can fit a 15t front sprocket to up the top speed to about 85mph, which is better for road use, and still allows good acceleration. This is enough power to redline the kmx125 in 6th, and gives 80mph on std 14/48 final drive gearing. It will then have 24bhp or between 20-21bhp at the rear wheel. No rejetting is required on any u.k spec and most european spec bikes. It is a welded in restrictor in the entrance to the expansion chamber, it looks near enough the same as the NSR125 restrictor with 3spot welds, that more people on here are aware of. Later KMX's certainely from 97 onwards have only one restriction. Remove the exhaust there *may* be a washer welded in it where it leaves the head. Newish ones there is a restricting rubber sat between the carb and airfilter. Also there is a chance that there is a piece of rubber inserted in the space between the carb and airfilter. If you are not happy to do this and worry about your own mechanical experience then don't do it.Īfter removing the washer and altering the valve you may need to re-jet the carb. I am fairly sure the de-restricted KMX was good for 21bhp, you are doing all of this at your own risk as the extra power will put more strain on the engine and almost certainly will reduce its life expectancy. It will be logically positioned at the front of the engine on the exhaust outlet. If you have the blanked off KIPS valve then you just need to remove the cover and rotate the valve. With a flat file or maybe a hacksaw blade you should be able to remove the section of weld that holds it in place and remove the disk
![kawasaki kmx 125 wheelie kawasaki kmx 125 wheelie](http://www.roadsmile.com/images/kawasaki-125-kmx_brown_13.jpg)
IIRC you will see the washer (?) inside the exhaust header (nearest the cylinder head) and it will be mounted to the outer edge of the exhaust at at least two points.
![kawasaki kmx 125 wheelie kawasaki kmx 125 wheelie](https://i.ytimg.com/vi/MhzEUDg3wPk/maxresdefault.jpg)
If it is restricted as I thought then first off you need to remove the exhaust.