1999 KX125 cylinder replacement?

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9/27/2018 12:59 PM

I picked up a 1999 kx125 recently for a Splitfire PC build, only to find that the cylinder is totally shot.

Im having a difficult time finding a new cylinder to replace it with -

my question is - the service manual groups 99-02 kx125's, but its my (limited) knowledge that the cylinder and pistons are NOT interchangeable. Is this the case? I have found a few bikes being parted out for sale that have 2002 cylinders. Simply put, can I replace my 99 cylinder jug with a 2002 cylinder, then install a '02 piston?

Really appreciate any expertise here!


9/27/2018 1:04 PM

why don’t you just send the cylinder out to have it repaired and replated?


9/27/2018 2:55 PM

It looks to have already been replated, plus someone rethreaded 2 of the head studs (making oem studs not able to seal) and the other 3 are stripped bad.

I did reach out to US Chrome about it already but haven't hear back...


9/27/2018 5:08 PM

i have a 00 cylinder on my 2002. I guess the opposite works too


2002 KX125 (SOLD)/2001 KX250 (SOLD)
1999 KX250 (SOLD)
2016 RM-Z250(SOLD)
2018 KTM 150XC-W(current)

9/27/2018 5:44 PM

get ahold of millennium technologies. Hands down the best cylinder repair shop in the world. I dont doubt they can repair your head stud threads either. Weld it up and re-drill and tap. Any machinist should be able to handle that one.


9/29/2018 1:05 AM

Some different cylinders have different power valve systems.

The last four digits of the part number are on the cylinder, cast in.