Changed out the fork oil and seals in our 2001 GS500. I'm changing the springs to Sonic Springs. So I saw that the recommended air gap is ~120mm (no higher with the stiffer springs) while the factory recommended oil amount to put in is ~382ml. So we put in 382ml. When we checked the air gap though, it was nowhere near where it should be, somewhere around 200mm if not more. I have the springs and spacers out and the forks are fully compressed. To get to 120mm, we had to put in another 100ml about. Does this sound correct?? I really don't want hydraulic lock but the air gap was super low when we put in 382 ml.
The only thing I can think of is that the forks were totally dry. Completely disassembled and cleaned. But I don't know that that would account for that much extra oil...
While I am not 100% sure I think the problem is that you should be measuring with the springs and spacers in place. They displace some of the oil and cause the oil level to be higher. Use a turkey injector to pull 100ml back out and measure with the springs and spacers in.
The air gap is checked with the spring removed and the inner tube fully down. (assuming the fork is removed from the bike)
Quote from: Sandgroper57 on August 05, 2019, 02:34:36 PM
The air gap is checked with the spring removed and the inner tube fully down. (assuming the fork is removed from the bike)
That's how I did mine too.
Fork fully compressed, no spring or spacer or washers etc, the air gap set to 120mm, and spacers cut to 115.5mm (I installed .75 Sonic Springs).
I didn't measure the amount of oil... I only paid attention to getting the air gap right. :dunno_black: