Backplate/ 20x1.4mm O-ring (for engines w/o starter) (TRX 2.5, 2.5R, 3.3)

The aluminum backplate replaces the EZ-Start? drive unit on the TRX 2.5, TRX 2.5R, and TRX 3.3 Racing Engines. It allows more efficient fuel/air mixture flow through the crankcase and significantly reduces overall engine weight. It's perfect for building that racing version of the Nitro 4-Tec or other racing model that is using a rear exhaust TRX Racing Engine. Using the backplate requires an electric bump starter and should only be used on models with unobstructed flywheel access. If the engine was originally equipped with a starter, then a different crankshaft is also required. Use Traxxas part 5288R (IPS) or 5289R (multi-shaft) crankshaft.