Immediate Help Installing Piston!!! Please

[elovelace256]

I am in middle of a rebuild on a 99 cr250. I have a oem piston but it does not tell me which was to install it.
The only markings are on the top. One one side it says IN and on the other it says 3V. I am assuming IN means the side of the carburator?
This is my first rebuild and im already stuck :bang:

Thanks for quick help!!!

 

[motogps]

The intake side is the side where the the skirt has the half circle cut out on it and where the ring gaps are and I guess it should say --in- but some pistons don't. There may be an arrow that points to exhaust side too.

John

 

[ellandoh]

this article will help

http://www.eric-gorr.com/twostktech/pistondiaguide_2t.html

it says there should be an arrow towards the exhaust port

 

[TimberPig]

Just make sure the ring locating pin(s) are towards the intake. If they go towards the exhaust, the rings will snag a port and break.

 

[2-strokes-4-life]

i am pretty sure all oem honda pistons have the IN mark on them. it should be pointing to the rear of the bike (intake side) i know on my 60 and 125,both pistons have the IN mark on them.