My manual states that from the step in the main tube with the rod extended and a few short pumps, you should hav around 45mm oil above the step. If there is to much you will find it hard to push the base valve bit in, (don't forget tho showas have bleed hole in so you can bleed off excess oil). It also states that once the base valve is in and all bled the rod should be able to push all the way out if held horizontally, If it doesn't you have air in there. Again this is for showas, but I think kyb's don't have bleed hole either so maybe they have a similar method.
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