I installed a new piston in my honda 250r, but i'm not sure if i put the piston in the right way.
the piston had a arrow on top and i had it facing the front of the bike. I tried to call a bike shop but they were all closed,
and i didnt remember to look at the old piston before i pulled it out and this is my first time ever rebuilding this motor.

 

I think you did it right. If I remember correctly, the arrow goes towards the exaust port. If I'm wrong, someone will chime in.