southdownhobby
New Member
Hello everyone,
I'm in the process of replacing the crankshadt my 951 (carb). The WSM crankshaft looks balanced as the counterwieghts are matched and 180° to the opposite pair.
I'm concerned about a slight misalignment of the shaft components at factory assembly. The following method was used to obtain a measure of this discrepancy:
I did find the gear alignment mark on the mag side and marked the notch on the visible pto side.
As I matched this notch with the marked counterbalance shaft tooth and seated everything properly; I rotated the crankshaft so that the proximal counterwieghts edges were both horizontal/flush and level with the crankcase flange/plane. I then took note of the counterbalance shaft's counterwieghts and it's orientation to the same plane. I placed a razor blade flat upon the case flange (case half mating surface) to scratch a mark on the counterbalance shaft gear. The counterwieght edges of the counterbalance shaft did not appear to be parallel with the crankcase flange.
I repeated the process with the original crankshaft (which does appear flush with both shafts) to demonstrate a slight difference (1.5mm) in the marks made.
Will this condition result in vibration or timing issues in respect to "top dead center"?
AI generated answers assume my 1.5mm measurement applies to runoff specs, but the shaft alignment itself is true and <.005.
I've attached images of both crankshafts set for marking. The Mag flywheel was marked at disassembly. This is my RX... not an RXDI, so if someone could assure me with how this might effect timing/ balance or not, please chime in.
I'm in the process of replacing the crankshadt my 951 (carb). The WSM crankshaft looks balanced as the counterwieghts are matched and 180° to the opposite pair.
I'm concerned about a slight misalignment of the shaft components at factory assembly. The following method was used to obtain a measure of this discrepancy:
I did find the gear alignment mark on the mag side and marked the notch on the visible pto side.
As I matched this notch with the marked counterbalance shaft tooth and seated everything properly; I rotated the crankshaft so that the proximal counterwieghts edges were both horizontal/flush and level with the crankcase flange/plane. I then took note of the counterbalance shaft's counterwieghts and it's orientation to the same plane. I placed a razor blade flat upon the case flange (case half mating surface) to scratch a mark on the counterbalance shaft gear. The counterwieght edges of the counterbalance shaft did not appear to be parallel with the crankcase flange.
I repeated the process with the original crankshaft (which does appear flush with both shafts) to demonstrate a slight difference (1.5mm) in the marks made.
Will this condition result in vibration or timing issues in respect to "top dead center"?
AI generated answers assume my 1.5mm measurement applies to runoff specs, but the shaft alignment itself is true and <.005.
I've attached images of both crankshafts set for marking. The Mag flywheel was marked at disassembly. This is my RX... not an RXDI, so if someone could assure me with how this might effect timing/ balance or not, please chime in.
