I need to rebuild an RM 125 that I bought used a long time ago. Last year I replaced the piston. After the rebuild if fired right up but sounded "off". Every other time I started it it sounded worse and worse until it just would not run. After fucking around with it for a while I threw the old piston back in and it ran great. I just took the piston out again b/c it has to be changed but there are no markings on the piston at all. all it says on the piston is ART on the inside any one know if this is a stock suzuki part and maybe I got the wrong size piston the last time or this is an after market piston and maybe my bike has been bored out?
Has the cylinder been sleeved or replated? if it has been replated it will have some numbers stamped on the intake side. Photos might help. If you can measure, the stock bore is 54mm. What year??
I don't know how to tell if it has been replated but it seems like a compant PR2 worked on it. it has a sticker on the cylinder and PR2 has been engraved on it. On the intake side it has been ingraved with C5VIE. Bike is a 2003 RM 125
The numbers on the cylinder are stock. The piston appears to be stock as well from the pics. Is there anything on the dome of the piston? Might have to clean off any carbon to see. Still be best to measure.
Nothing on top of piston except a circle to show it is the exhaust side. What is best to use to get an acurate size. Thanks for the help
Other than measuring, if the cylinder has not been sleeved or replated, you "might" assume it is stock bore. From the pics, there doesnt seem to be a number associated with a replate on the cylinder. if the cylinder has been sleeved, you should be able to tell with a magnet to the bore...if it sticks, it has been sleeved. In the end, a measurement of the piston or bore would tell. With no number on the piston crown to what appears to be an OEM piston, I would think it is stock bore. A pic of the top or bottom of the cylinder might help.
