fork oil change - outer chamber only?

My fork seal leaked out a pretty big puddle after it got some dirt in it yesterday. I fixed the seal with the tear-off trick, but now I want to replace the oil so I know it will be at the right level. Right now im at the point that Ive taken the fork cap off and drained all the oil out of the outer chamber. about 18 oz came out, but the manual says the total amount should be about 22oz. The bike is fairly new, it has less than 30 hrs on it. I want to be riding by friday, so what is the easiest way to get my oil within spec? can I just dump about 19 oz into the outer chamber and put the fork cap back on, or do I absolutely have to take apart the inner chamber and drain the oil out of it? the bike is an 08 yz250f with stock KYB

it's better to have the same qty of oil in both forks.

the fastet way would be to take the cartridge off, reinstall it and pour in 330ml of 5wt oil

And do it on both legs.

If you don't want to remove the cartridge then you have to let the fork rest for a couple of hours upside down to make sure all oil is out.

Ok thanks. If I dont remove the cartridge, how will i know how much oil to put in? just go by how much drained out? and also I only have 7w oil, i hope thats not a problem

i always just clean the forks completely of oil, but i also take the cartridge off and insure the amounts are right on with a measuring cup.

Without taking the cartridge off id be willing to bet a couple hours upside down and there will be no worries.

Outer chamber only is fine. I would do what frezno mentioned though and do both. You need the same level in both forks and the same type/brand/weight in both forks.

You need the same level in both forks and the same type/brand/weight in both forks.
I'm going to propose the radical notion that that simply isn't true. Sure, it's technically more correct, but it's not absolutely necessary. There are any number of tuners who will mix springs to get a rate in between the two, and several OEM and customized forks exist that do compression damping on one side and rebound on the other. Then there's the new KXF250 fork with one spring.

But the OP is probably not so pressed for time or money that he should not do it right.

To clarify what frezno said, the cartridge doesn't need to be removed, just unscrewed and the outer fork drained, and the correct amount replaced in both sides. In a rush at the track between motos, you could fearlessly do one side only, IMO.

To clarify what frezno said, the cartridge doesn't need to be removed, just unscrewed and the outer fork drained, and the correct amount replaced in both sides.

right, i wasn't talking about the compression unit but the whole thing within the tubes

ok thanks everybody. I unscrewed the cartridge and replaced the oil in it as well. I only put 300ml in the outer chamber as a starting point for tuning. If i want to add 5-10ml at a time , can i inject some into the air bleeder valve at the top of the fork?

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