| JS lightweight bare pistons | 750cc = 185 g | 850cc = 210 g | |
| Stock Hepolite bare pistons | 750cc = 250 g | 850cc = 317 g | |
| JS bushless Carrillo rods | small end 105 g | big end 326 g | |
| JS bushless Ultralight Carrillo rods | small end 95 g | big end 307 g | |
| JS DLC pin | 750cc = 51 g | 850cc = 58 g | |
| Stock pin | 750cc = 68 g | 850cc = 72 g | |
| JS Beehive valve spring | 42.3 g | TI retainer 4.7 g | Street seat pressure 90 lbs Race seat pressure 130 lbs |
| RD racing spring | 59.3 g | TI retainer 10.8 g | Race seat pressure 130 lbs |
| Stock spring | 59.7 g | steel retainer 16.1 g | Street seat pressure 90 lbs balanced with shims. 100+ lbs shimmed for racing |
| JS (BSA) radiused lifter | 38 g | ||
| Stock flat lifter | 74.6 g | ||
| JS pushrod | 31 g | ||
| Stock pushrod | 32 g |
JS Motorsport Technical
