A very good airhead guru recommends balancing the carbs on the R65 by a very simple and effective method. I tried it and works very well.
You warm the engine as always before balancing.
Then give the engine a slight amount of throttle.
Now using three fingers slightly depress the throttle cable on any cylinder.
If the engine speeds up and evens out then that cylinder is behind the other.
Depending on the engine speed you can bring back the other cylinder or increase the one you are pinching.
When balance is correct there is no engine speed increase at a slight amount of pinching. If you increase the bend in the cable you feel the engine speed up but miss as that cylinder starts to lead the other.
Its simple, fast and effective.