how do i tell if i still have the stock piston in my kx?

[kix500]

my bike is a 97 kx 500 and i was going to re ring it but im not sure how to tell if i have the stock piston or if some one has replaced  it with an after market one. any way to tell?


cory

[gowen]

Cory, usally aftermarket pistons are stamped on the top. I've not seen a stock KX piston is many moons. But, I believe that they have a A or B stamped on the top. Usally Wiseco or Pro-X have the bore size stamped in the center. Clean off the carbon and read what numbers are on the top. Make sure you don't use to hard sand paper or wire brush as they take the numbers off. Try to clean the top and tell us what it reads.

[kix500]

i decided not to tear it down just yet i took it out tonight and wow she is running sweet so i think i will wait a while but when i do i will let everyone know what i find.

cory

[SupermotoFan]

I'm hijacking this thread to ask about my piston.

It has no size marking on the crown, only a directional arrow.  It also has the letters "ART" in the indentation near the wristpin, and it appears to have "+2" on the inside of the skirt.

Anyone recognize the markings?


SupermotoFan
'86 KX500

[demographic]

I'm hijacking this thread to ask about my piston.

It has no size marking on the crown, only a directional arrow.  It also has the letters "ART" in the indentation near the wristpin, and it appears to have "+2" on the inside of the skirt.

Anyone recognize the markings?


SupermotoFan
'86 KX500

Well as far as I would say it, ART are the Japanese company that makes all the cast pistons for Japanese bikes.

They also make oversize pistons and by the +2 designation on yours I would say that its 2mm oversized and had a few rebores.
Standard piston is only a gnats pube less than 86mm so I assume that yours is only the same amount less than 88mm (for more accurate measurements and to find the correct piston to bore clearance its best to check your manual) so if you measure it you should be able to back this up.

I would have said that you always point the arrow towards the front of the bike but that was before I heard of bikes with reversed cylinders so now just remember to face the arrow towards the exhaust port.

Regards Scott.