YZ-4 Belt Tensioner Upgrade - Yokomo Z4-BTS  [Z4-BTS]

Aluminum tensioner designed for YZ-4 transmissions

This Z4-BTS belt tensioner set is an RC-scale accessory tailored for the YZ-4 platform to manage belt tension and allow fine positional adjustment of the idler assembly. The holder is machined from aluminum and finished with a beveled edge to reduce interference inside the transmission area.

The set includes two different screws for selecting the correct bearing offset between front and rear locations, plus a spacer to shift the bearing position as needed. Use the appropriate screw for the intended axle position and verify belt tension after adjustment to prevent slippage or excessive preload.

Installation is straightforward for experienced hobbyists: remove the original idler, mount the aluminum holder in place, choose the screw that matches front or rear offset, add the spacer where required, and re-check belt alignment during a short test run. This component serves a tuning role rather than altering primary drivetrain geometry.

Compatibility

• Supported Chassis B-YZ4