piston replacement on 1997 250 sx

piston replacement on 1997 250 sx

Posted in the KTM Motorcycle Forum


Salem, MA

#1 Aug 12, 2007
I have a wiseco piston to be placed into my KTM and was reading the instructions with the piston. In them it stated that "if the cylinder has an exhaust bridge the piston should contain lubrication holes on the skirt where it contacts the exhaust bridge. if the piston does not have the holes they need to be drilled into the piston."

The cylinder is brand new due to the fact that I seized the engine after replacing the previous piston. the circlip from the piston ring came off and got lodged between the piston and cylinder sleeve. as you would expect the previous cylinder was in need of replacement.

Please provide any insight on the exhaust bridge and the need to drill these holes in the piston, as well as any other tips on replacing the piston.

piston part #694M06750


Taunton, MA

#2 Dec 30, 2007
I jut had my 1992 Suzuki RMX250 head sent out for a sleeve repair and had the power exhaust cleaned and reinstalled. I ordered the wisco piston kit and drilled the two holes below the ring groove (skirt). This was new to me and I didn't feel too good drilling into the piston but I did this after finding some more details on line. Well now that I have my bike back together the bike starts and runns but as soon as it warms up I'm getting a slight knocking out of it an need to find out what is going wrong. My feeling is that the noise is coming from the exaust valves and the RPM's are also jumping around. I don't feel the piston holes caused this issue.
Good Luck and remember to mark the correct side of the piston.

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