Oil front fork beta evo 125 - Beta Motorcycles

SOURCE: KX 125 (2003) motorcycle

its 120 mm or 4.7 inches from the top of the fork
Some measure the oil quantity and fill the fork up, some fill the fork up and measure the oil level. The most correct method is to measure the level, I guess, but many guys measure in quantity.. both ways work well.

SOURCE: front fork oil capacity

Hi
You can download the whole workshop service manual that has this info and heaps more from here. Hope this helps Thanks for using Fixya. 
regards robotek

SOURCE: front fork leaking oil from bottom of the seal.

change the oil seals and oil in the fork,and avoid wheelies on the bike and off road biking 

SOURCE: how much 5w oil goes into each fork?

Using 5w oil with stock springs, your oil level should be about 100mm from the top with the fork fully compressed, damper rod pushed all the way down, and the spring out. I hope this helps and good luck. Please vote and leave a message.

SOURCE: fork oil capacity

medium fork oil - 150 mls in each leg