[ntzman28]

Hello all,

Am re-ringing a Yamaha J38 out of an early 90s G9. I can tell as I'm taking it apart that someone in the past has probably done the same job: screws on the shrouds are marred, scratches on the crankcase side cover where it was removed before, use of only grey RTV on the cover and no gasket, etc. When I got to the piston, the arrow on the top was pointed towards the back/exhaust side of the head. Everything I've found online says the arrow should be pointed towards the front/cam side of the engine. As I lap the valves, hone the cylinder (looked good BTW), etc. while I await the replacement rings, I'm wondering if I should turn the piston around the right way, or if there is any harm or foul in doing so. Piston measures within tolerances, as does bore as best I can tell with what I've got to measure (dial caliper). I've heard that pistons are actually a little bit egg-shaped, but can't see that having it in with the arrow towards the back of the engine did any harm to the piston or cylinder. Should I take the wrist pin out and turn it around? I even thought about just turning the whole connecting rod around, but worry about uneven bearing wear at the crank. Was it a common thing for high-volume golf cart repair shops to turn pistons and con-rods around, and if so, what was the advantage in doing so? Thanks in advance for any replies. Am enjoying learning from everyone's prior posts. there is also a letter on the connecting rod bearing cap, and it was oriented towards the back of the engine as well.

Thanks,

ntzman28