Honda Grom/Monkey lightweight flywheel eliminates rotating mass from the crankshaft allowing the bike to rev up much quicker. 

CJR Flywheel ONLY 2014-2020 Model - 885g
OEM Flywheel ONLY 2014-2020 Model - 1237g

CJR Flywheel ONLY 2021 5spd - 903g (2lbs)
OEM Flywheel ONLY 2021 5spd - 1,378g (3lbs)

Timing marks will be slightly harder to see visually, it is recommended to remove the spark plug and insert a tool to verify TDC if you are unsure of the correct mark. 
*Custom machining can vary final weight slightly. Indicated weights are an average.