Now. . . Bam. . . Here ya go!
My experience is with mountain bike suspension where most of the forks use an air spring. This is primarily where the oil volume creates a drastic change in the ride. This is due to the volume of the oil having a direct relationship with the air volume. The more oil, the less air.
These scooter forks all seem to be very simple in comparison! I'm not certain that the oil volume will have such a significant impact on performance. The main thing is to make sure you don't have too much oil, this will create a hydraulic lock within the fork at the bottom of the stroke, and not feel good at all!
The oil weight in the scooter forks will allow for a good deal of adjustment. The heavier the oil the slower/stiffer the compression, but also the slower the rebound, as the two circuits are not independently adjustable. From what I discovered in trying to find oil volume/height for my Vento fork is it seems most of these forks use 15w oil. Some also specify ATF which is equivalent to 15w. I would recommend using specific fork oil though, it contains anti-foaming agents to control cavitation. ATF contains these also, which is why it can be interchanged, I've always just stuck with fork specific oil. Plus fork oil is available in different weights for tuning purposes, you can also mix weights to get a "custom" weight. Say equal parts 15w and 10w = 12.5w.
Hope this helps! Let me know if I can answer any questions for you!
