I asked my friend Lee Riddle to contribute his knowledge and experience tensioning the primary belt drive which is located on the left hand side of the bike. I will be augmenting his information in the future. Thanks Lee!
Most Sur-Ron’s come with belts too tight, you can feel the extra drag when walking bike across garage floor and it will be more noisy and less efficient when running. Essentially to adjust belt tension loosen all four motor mount bolts, lift motor to loosen tension, lower motor to tighten, equalize both rear lower bolts in sliding rectangle boxes, re-tighten.
NOTE silver tab of cam sticking forward on side of black motor case just below rear most yellow mark, make sure both sides have equal tension by measuring distance to slot bottom from bolt.