Im rebuilding my 74. How are the new pistons to be positioned? They each have a dimple on one side of the dome which to me looks like an indentation to accommodate the spark plug. The dimple is on the same side as the web-boss on the underside of the piston and according to the manual that web should be on the right side. Im wondering then what that dimple on the dome is for if not for the spark plug which is on the left side of the motor.

thanks

randy

 

it could be a casting end pore indent -- but a picture would help

 

the top of the piston should be smooth, to prevent carbon build-up, & detonation. make sure you stager the rings . & the first 20 miles on the new rebuild in most important.
ie 1. warm the bike up , accelerate hard from 20 to 60mph then let off of the throttle & let the bike de-accelerate back down to 20. 2. cool the bike off before shutting it off.