what are the differences in 98 kx 125 and 99

i have a 98 kx125 and im about to put a 99 jug on it. im finding sleeves on ebay saying it will fit the 99 and the 98. the only pistons i can find are for the 98 or the 99. so if the sleeves are the same why are the pistons different? can anyone help?

The sleeve can't be for both years. The '99 got an all-new top-end, with different porting, re-shaped power valve, different piston, different carb, and different reeds.

Why are you looking at sleeves? Don't sleeve your cylinder, get it re-plated if the bore is worn out or damaged.


No, i am needing a piston. my bottom end is a 98. i have the 99 top end with the exhaust and power valves included. do i just get the 99-00 piston and put it together? will i run in to any problems?

If you are using the '99 jug, get the '99 piston.

my bike is a 98 kx 125 and i am going to replace the jug with a 99 including the 99 exhaust valves. the part numbers for reeds on the two different bikes are different as well as the carb. so,...what efeect will it have by keeping the 98 reeds. . i would really like for someone to take to time to explain the differences in the 98 99 and 00 bikes. from the motor to the plastic on what parts will interchange and what will not. are they the same frame? different subframe? i would be very thankful for any info someone could give me. thanks a million

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