EVERY engine we build is dynamically balanced and indexed with all components of the rotating and reciprocating masses.. If the engine is spec'd with a LWF, it would be balanced in the assembly. In some instances we'll balance two flywheels to the engine for a choice that doesn't impose imbalance on the engine, or some times we'll balance a spare pressure plate too...

The LWF imposes imbalance and a lac of harmonic dampening when applied to an engine thats already assembled... Neither of those are good, both of them together can break a crank just like what the X 51 on my deck now has.