Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
What I am about to suggest may be frowned upon, but it works. I have a wire brush with just the right size wire that goes into the main orifice on the pilot jets on Teresa's old CB550F2, which I had to use when I was about to sell the bike. It wouldn't run on all four cylinders, so used the wire method & it worked quickly & easily. One of the problems with this method may be that the pilot jet size for the 400F are smaller than the 550F.Machine Mart now sell an ultrasonic parts cleaner. This might be a good & worthwhile purchase.Good luck.