A whining noise on a motorcycle that occurs at a specific speed and goes away when leaning for a turn can be caused by a few different factors. Here are some possibilities:
Wheel Bearings: Worn or damaged wheel bearings can produce a whining noise at certain speeds. When you lean the motorcycle during a turn, it shifts the load on the wheels, potentially relieving pressure on the worn bearing and reducing the noise.
Chain or Sprocket Issues: A worn or improperly tensioned chain, or damaged sprockets, can create a whining noise. Leaning in a turn may affect the chain alignment and tension, temporarily reducing the noise.
Tire Wear: Uneven tire wear, such as cupping or feathering, can cause noise at specific speeds. Leaning into a turn may change the way the tire contacts the road, altering the noise pattern temporarily.
Belt Drive Problems: If your motorcycle has a belt drive system, a worn or misaligned belt can cause whining noises. Leaning in a turn might affect the tension or alignment, momentarily altering the noise.
Transmission Issues: Problems within the transmission, such as worn gears or bearings, could produce a whining noise. Leaning during a turn might change the load on the transmission components, momentarily affecting the noise.
It's important to note that diagnosing a specific issue without inspecting the motorcycle in person can be challenging. If the noise persists or worsens, it would be advisable to have a qualified motorcycle mechanic inspect your bike to identify and resolve the problem.