If you examine the crank, there are huge counterweights to both provide inertia and oppose the dead weight of the rod throw 180° away.
I've read many articles on L6 balancing, and have yet to see a specific recco as to what mass the individual counterweights carry, or even the total imbalance.
Obviously, 100% of the rotating weight is included (pin, arm, bearings, rod big end), but what (if any) opposes the reciprocating weight?
Why are some counterweights heavier?
The only definition is what it's not: it isn't a percentage of the reciprocating weight (which is what V8s require).
