RE: improved vibration
Having more thoughts on rebalancing the crankshaft I an inclined to think that the counter weight is much heavier than it needs to be. The "factor" used to calculate the mass of the counterweght is determined from extremely accurate weighing of the piston and its components and then a portion of the connecting rod. This is usualy done by weighing the small end with the rod suspended from its main bearing center and resting the small end on an very sensitive scale in the horizontal position.The balance factor is a percentage of the sum of those parts weighed. often around 60%. A weight of the value calculated is placed around the crank pin and then the whole crank is made to stop at any position similar to when balancing a prop. Alot of experimentation is usualy involved to find the best amount of counterweight that will balance the bits going up and down against those going round. Just my observation but there seems to be an awful lot of metal in the counterweight of the RCV 120.In the case of this engine we have an extra consideration, the flywheel effect of the driving bevel gear attached to the crank and the large spinning gear and sleeve valve/cylinder. Could it be that the mass of the driving bevel gear is working against the purpose of the counterweight on the crank? I am so desparate to get a smooth running RCV that I am prepared to experiment as soon as I can locate the right weighing equipment. watch this space!!! any one else with ideas?