[xb-60]

Originally Posted by CHANMADD

Most engines have an imbalance at 1400_2000 rpm. This is harmonic imbalance.The harmonic balancer helps to absorb that frequency. Most harmonic balancer have arubber ring sandwiched berween two parts. This type of balancer should be balanced with the crank. A fluid filled type balancer cannot be spun balanced because the fluid moves around. The 28 oz thing is like balancing a wheel and on one side there is a big hole drilled , so that before you stick it on the machine you know that you drilled out 28oz, so that exactly opposite at the same circumference you attach a 28oz weight to get the balance close before spin balancing on the machine.
A single cylinder motor would have all the components meticulously polished ,shaped etc.
A blueprint is making sure that all the components match exactly the designers specs.
A multicylinder blueprint is making sure that all the cylinders and all related components are exactly the same, down to 0.002 of a gram. When they are all same the harmonics will be minimized and then spin balancing will require less addition or removal of metal. This is what makes motors live.
Look at the pulley on a good timiing chain set...it should have some balancing drill marks.
So....yes balance everything if you can..it can only make things smoother
John

John - if you drill a hole on one side and then add material exactly opposite, would that not make the imbalance worse?
Cheers,
Glen