No, not all bikes without a clutch have automatic transmissions. While many motorcycles without a clutch do have automatic transmissions, there are also bikes that use other types of transmissions.
Here are a few examples of different transmission types found in motorcycles:
Manual Transmission: This is the traditional type of transmission that requires the use of a clutch lever and manual shifting of gears by the rider. Most motorcycles, especially those with larger engines or geared towards performance, use manual transmissions.
Automatic Transmission: Some motorcycles have automatic transmissions that do not require the rider to manually shift gears. These transmissions can vary in design and operation, but they typically use a torque converter, a continuously variable transmission (CVT), or an automated manual transmission (AMT) to manage the gear ratios automatically.
Semi-Automatic Transmission: Also known as a "clutchless manual" or "quick-shift" transmission, this type of transmission allows the rider to shift gears without using a clutch lever. Instead, the rider can shift gears using a shifter mechanism, while the system automatically disengages and re-engages the clutch. It provides a more convenient shifting experience compared to a manual transmission but still requires manual input from the rider.
Dual-Clutch Transmission (DCT): Dual-clutch transmissions use a combination of manual and automatic transmission features. They have two separate clutches—one for odd-numbered gears and another for even-numbered gears—which allows for quick and smooth gear changes. DCTs can be operated in full automatic mode or manual mode, where the rider can manually shift gears using paddle shifters or buttons.
It's worth noting that the availability of different transmission types can vary depending on the motorcycle model and manufacturer. Therefore, when considering a specific bike, it's essential to review its specifications or consult the manufacturer to determine the type of transmission it utilizes.