Has anyone had any luck balancing a crankshaft on a 60’s big twin? It seems that these engines weren’t built with a decently balanced rotating assembly. I’m curious to see if anyone has had any experience with this? I have several crankshafts and they all seem to settle differently while laying horizontally on a balancing rail.
Yeah, I tried it. Removed shocking amount of metal. Motor vibrated as much or more than it did before. Conclusion: There is more to it than meets the eye.
What amazes me is that the same crankshaft is used with the two ring 70’s 40hp engines and that piston and rod assembly is over two ounces heavier than the three ring assemblies of the earlier models. I guess they just weren’t worried about vibration.
The pulse from ignition also needs to be considered.
It has a considerable effect on single horizontal firing
Motors. The more even the pulses around the rotation
of the crankshaft the less effect in has on vibration.
V-12’s & V-16 being the smoothest even in the 1920’s & 30’s
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.
A lot more complicated that meets the eye!! talking to an automotive engine designer ( we have several up here around Detroit) and you just begin to understand the complexity of engine "balance".
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