Originally Posted by
cathurga
For those that have done the Walbro conversion, I am having some problems getting it tuned.....(I thought this would go away with the walbro)....what needle settings did you end up with. I don't know what they were to start with, I shoulda checked....but I am getting some odd symptoms from bad tunes. I am good at getting the 2-strokes tuned, but this is not behaving the same...
Cathurga, the original Carb is a Walbro as well, made on spec from Saito.
All the original Saito-specified Walbro -Carbs are most likely much better carbs than the Chainsaw Carbs from Walbro, normally used on two strokes.
Remember ;
A Chainsaw basically needs only idle and max. Something in between is of no interest. So the chainsaw carb has just a circular plate inside that opens and closes ;
That's your throttle.
The result is that you get a highy unlinear airflow, especially when you opens it, from fully closed.
That again results in that people put in expo on the throttle, to try to get a better control around idle......
The Saito specified Walbro carb has a piston, and a needle in the middle of the piston.....much better control of airflow.
Otherwise, the pump mechanism is equal.