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Todd - You have presented a a very well thought out hypothesis, which in some ways does make sense. However, the counterweights on a crank (not sure if Deere has them, I know that most antique tractor 4 cyl's are not fully counterweighted) are meant to counteract transverse loading of the crankshaft, as you mentioned. This is to reduce the stress on the bearings, bearing caps, and block and crankshaft. The crankshaft damper is to help reduce or eliminate torsional harmonics or torsional shock loading to the crankshaft. Any crankshaft can only take a finite number of cycles (torsional or transverse)at a given loading before breakage. If you increase the number of cycles for a given length of time (increase RPM) the breakage limit will arrive much sooner. The same can be said for increasing the loading at the same rate of cycle accumulation (increasing torque through displacement or compression, detonation, etc). The net result of either of these is the same: It won't live as long! Now, if you take a torsional harmonic damper and put it on the end of your crankshaft, it will "clip" the top ends of those loading spikes (from cylinder firings) off, thus decreasing the torsional shock load to the crankshaft. Similarly, if you fully counterweight your crankshaft, you will decrease net transverse loads from cylinder firing. These two things have the reverse effect of what was mentioned in the previous paragraph: the crank lives longer at the same rate of cycle accumulation (RPM). It is my suggestion that a torsional damper or fully counterweighted crankshaft in a JD 2cyl would show you nothing measurable on a dyno or in the life of the crankshaft (at stock + X% RPM). When you spin the engine up, it is a completely different story.... Regards, Goldsburg
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