Bolted right on without any modifications and the bike is finally running to its full potential
I bought this kit so I could be running a 125 piston instead of the 144 and the bike runs great it is super crisp and the motor feels awesome. Also it gives good instructions on how to build the head and everything.
I bought this for a 2003 kx125 and man did it bring it back to life plus some. My 2003 can keep up with modern 125’s with this kit.
Easy to install and give tons of power.
Purchased a stock bore Athena replacement cylinder. Would've been nice to know they intentionally spin the stud bold holes 180 degrees so you have to buy their cylinder head. Next time I'll just spend the extra money and buy an OEM jug. Not worth the hassle of going aftermarket.
With v force reeds this thing runs super clean and crisp. Good power.
My stock cylinder was trashed. Picked up the Athena kit and after the simple install there was noticeable performance gains.
Bought this kit for my YZ125 that I had blown up. It was super easy to install and got me back into the season without missing a race and the bike seemed to have a little more power also.
more details can be found here: http://www.athenaparts.com/files/pdfs/P400485100003.pdf