1. Break

The drive belt breaks sometimes. Some Sparrows break belts more often than others.

Replacement belts are made by Gates Rubber. The belt is called a Polychain GT2 8MGT-1600-36. They can be ordered on-line from LIMCT http://shop.limct.com/?page=shop/flypage&product_id=734&category_id=7182a3248421827f9b262cb8192b9d29&

2. Squeal

Improper alignment or excessive tension in the belt makes it squeal. Solutions include:

plating the rear sprocket
lubing the belt
- Do NOT use lubricants that contain solvents that might harm the belt!
cleaning the belt