Fixing that elusive Honda CB brake squeal - really!

Just about anyone who owns a 70's Honda CB (350, 400F, 450, 500, 550, 750 - did I miss any?) knows these brakes tend to squeal.  Honda builds some great machines and they get credit for being one of the first motorcycle manufacturers to put a disc brake on their street bikes.  This disc brake design leaves something to be desired though.

I've been riding my CB550F around the island and enjoying it, EXCEPT when using the brakes.  That squeal is annoying, even with ear plugs on.  The sound can be modulated by varying brake lever pressure.  But let's face it, when we're using the brakes we just want to concentrate on stopping and not noise levels.

So I had been doing this and that upgrading the brakes and hoping to get rid of that noise.  Some of the upgrades included a new brake piston (Kevin 400F's from the sohc4 forum) made out of a hard plastic that will not corrode, Ferodo brake pads from the old days with asbestos braking material along with the master cylinder and new braided lower line mentioned in earlier posts.

The brake's stopping performance has been great!  Just that sound...

So here's what I recently did attempting to fix the problem:

1. Read through numerous posts on the Sohc4.net forum about brake squeal.
2. Bought some high temp grease, cleaned the outboard brake pad off and coated its metal surfaces (not the brake pad material) then reinstalled it.
3. Put "disc brake quiet" on the back of the inboard brake pad.
4. Rode around with a loud brake squeal, except for just a few times here and there when it went away.

Well I had a LITTLE luck with that!  A few days later I went back and read those same forum posts again and:

1. Removed the arm that holds the disc brake pad assembly.
2. Lubricated the pivot pin and o-rings with the high temp grease.
3. Reassembled and lubricated the adjustment screw that aligns the brake pads to the disc.
4. Cleaned off the brake pad that I had already lubricated with high temp grease and then lubricated it with that same grease AGAIN (on the metal surfaces and not the pad material).
5. Used 150 grit sandpaper and scratched up the surfaces of the brake pads.  Also gently chamfered the pads on the side where the disc contacts them first (the side closer to the motor).
6. Lightly sanded the outboard side of the disc brake with the 150 grit sandpaper.

Went out on a riding about 100 miles and almost no squeal!  Hard to believe.  It was great.  Then... the noise started coming back. 

I believe the high temp grease layer between the caliper piston and the pad kept the noise away (for awhile).   That is, until some of the layer squeezed out from between the piston and the pad.  So I took the caliper apart again, put disc brake quiet on the back of this (brake piston-side)  pad, let it dry thoroughly and placed it back in the caliper.  The idea was letting the disc brake quiet dry thoroughly before reinstalling would help it set up on the back of the pad so it wouldn't squeeze out.  It took another week until I had time to ride the Honda and I'm happy to report no more brake squeal.