Purchased some .010 pistons for my 124 and it seems both are marked with an F indicating front piston. That being said the part numbers are 920-0020 (front) And 920-0021(rear)

I’ve done several of these and never seen an F on the rear piston. As as seen in the STD piston a clear F and R

just to be clear if I were to use the F as the front of the piston id be be running a boxer style engine.

SS says no worries, I say something it’s t quite legit


thanks

 

I would check to see if the wrist pin is offset, also if there is a relief cut on one of the piston skirts and match to your old ones.

 

What do the skirts look like? The one with the cut away will be the rear piston..