There are three motorcycle controls involved in shifting smoothly; the clutch lever, gear shift lever, and the throttle.
- Clutch disengages and engages the power from the engine to the rear wheel. Using your left hand to squeeze the clutch lever fully disengages the power from the engine to the rear wheel, preventing the motorcycle from moving forward regardless of how much you roll on the throttle. As you slowly release the clutch lever, you will encounter the friction zone. The friction zone is the point at which the clutch begins to transfer power to the rear wheel and the motorcycle begins to move forward. When locating the friction zone, we use minimal throttle roll-on.
- Gear shift lever is located on the lower left side of the motorcycle. The gear pattern is laid out with first gear at the very bottom, followed by neutral, first, second, third, fourth, fifth, and sometimes sixth gear.
- Throttle is located on the right end of the handlebar. Rotating your right wrist towards you increases the amount of gas you are feeding the engine (rolling on the throttle). Rotating your wrist away from you feeds less gas to the engine.
Tips for a Smooth Shift:
- Disengage the clutch by using your left hand to squeeze the clutch lever completely.
- Select the appropriate gear by using the gear shift lever (tap down to get to a lower gear or pull it up to shift to a higher gear).
- Roll on the throttle by slightly twisting your right wrist toward you (starting from a wrist flat position).
- Gradually release the clutch lever with your left hand (Do not pop it suddenly) while gently and steadily rolling on your throttle with your right hand, accelerating the motorcycle.
- Release the clutch fully and accelerate matching your engine speed with your ground speed. Then repeat the process to shift to another gear.
At lower gears engine is rotating higher speed than the gear box, as you shift up this difference reduces and by fourth gear (typical 5-speed gearbox) both are equal and by fifth gear gear box is running faster than engine. Engine rpm drops when you up shift and increase while shifting down. When you engage the clutch if the difference between engine and transmission is almost correct, the whole gear shift becomes very smooth. So while shifting up let go off accelerator so that engine rpm drops and while down shifting just before leaving the clutch give a small nudge to accelerator to increase the rpm a little. This is called rev-matching and if the difference is correct one can even do clutch-less gear shifts.
Reference :- How to Shift Gears on a Motorcycle