The red line is the standard 10 thou setup and you can see the ratio of fuel /oil starts off at around 90:1. This reaches 20:1 at around the ¾ throttle position after going through various values according to throttle position. It stays at approx 20:1 right up to full bore.
The green line is the setup with the minimum stroke set to 12 thou. Here you can see the ratio starts off at 75:1 and also has various values along to the ¾ throttle position. Oiling is increased between tick over and the ¾ position.
The blue line is where I run my bike, with the stroke set to 14 thou. You will see from the graph that the ratio starts off at 64:1 and follows the same curve as the other two values, although oiling between tick over and the 3/4 throttle position is increased still further.
As many people run pre-mix at 30:1 or so, I see no reason why the bikes should run 90:1 at any time. The pumps were set up back in the day to keep up with ever stricter legislation and poor quality oils compared with what we have today, (smoke issue). Indeed the early A/B air cooled models oiled much more than the later E/F models. There is not an issue after 3/4 throttle as 20:1 is plenty of oil even for a tuned engine. Graph is based on A/C models. The LC’s will be much the same.
HTH,
Arrow.
