The connecting rods of the opposing pistons engage a
common crankpin, resulting in alternating firing intervals of 54 and 90 degrees.
Most V - twin engines have a
single crankpin, which is shared by both connecting rods.
Further extensive lightweight design measures have resulted in such features as titanium connecting rods, thin - wall, low - pressure casting on the crank case and the cylinder heads, a high - strength, lightweight steel crankshaft with 180
degrees crankpin offset and the extremely thin - walled alloy steel / nickel exhaust system.
That called for a longer crankshaft, for which Reggiani had doubts about the strength of the old engine's split -
crankpin design, so the new engine's opposing cylinders share a common, unsplit crankpin and to hell with even firing intervals.
True boxers have
each crankpin controlling only one piston / cylinder while the 180 ° engines, which superficially appear very similar, share crankpins.