The LRP ZR.21 Spec.4 pullstart engine is a performance-optimized .21 nitro engine and is ideally suited as a replacement or upgrade engine for RTR stock engines.

Optimized port timing ensures strong power delivery and very responsive throttle behavior.

The engine setup is intentionally kept simple.

The ZR.21 Spec.4 can be tuned quickly and easily and impresses with clean and reliable running characteristics.

With its well-balanced combination of performance, ease of use and proven LRP nitro technology, the ZR.21 Spec.4 pullstart is the perfect entry into the world of LRP nitro engines. #32173