Challenger & Sapporo With Rear Disc Brakes

These models use a Blend Proportioning Valve (BPV), with a Red color-coding mark. It is located near front wheels.

The BPV accomplishes 2 functions. It improves braking efficiency by distributing braking force to front and rear wheels. It also increases braking force to rear wheels, when large braking force is required or front brakes fail.