Topic: '81 CB650 Inner front brake pad always touching rotor

[verro]

Hey! I have always had this problem since I got the bike. I thought it was a bad piston but after rebuilding the brake I see that is not the case.
I couldn't get a better picture because the wheel was obstructing, but the right brake pad did not have any room to move. The left one has plenty of room. I can still roll the bike around but there is an annoying resistance. I followed the schematic of the brake and I have all the pieces and it is assembled correctly. Does anyone know what the problem could be? Thanks for your help!

[HondaMan]

These days, it is not unusual to get some generic parts (like brake pads) that are not quite umm... exacting about adhering to Honda's 50-year-old specifications. This situation [edit] appears to me [/edit] to be one of those. The brake caliper, if it does not have a spacer screw for adjusting the non-moving pad's clearance from the rotor, will have to simply wear in the stationary pad to the minimum nominal clearance. This happens sometimes with the CB750F0/1 rear caliper: it has happened to me twice.

The OEM spec for the pad-to-rotor clearance for the non-powered pad is 0.1mm/0.004", if you have an adjuster for it. I usually set them a bit tighter, like 0.05mm/0.002" instead, as many of the rotors are not dead flat anymore, and this tighter adjustment will reduce the free-play in the brake lever.

I have had to 'reduce' the thickness of several brands of the pads (static pad side) in the past.

[scottly]

The pads are NOT installed correctly. The back of the inner pad should be sitting flat against the caliper body; there is a visible gap in the pic. The shinny spring plate thingy on the outer pad is upside-down; those tabs should be between the pad backing plate and the inside of the caliper body.(EDIT I need to verify the part about the spring plate orientation. In any case, it is the same for both pads.)

[verro]

The pads are NOT installed correctly. The back of the inner pad should be sitting flat against the caliper body; there is a visible gap in the pic. The shinny spring plate thingy on the outer pad is upside-down; those tabs should be between the pad backing plate and the inside of the caliper body.(EDIT I need to verify the part about the spring plate orientation. In any case, it is the same for both pads.)

There is no gap between the pad and the wall, or else i wouldn’t be having this issue. I also have installed the spring plate correctly, according to this:

[verro]

These days, it is not unusual to get some generic parts (like brake pads) that are not quite umm... exacting about adhering to Honda's 50-year-old specifications. This situation [edit] appears to me [/edit] to be one of those. The brake caliper, if it does not have a spacer screw for adjusting the non-moving pad's clearance from the rotor, will have to simply wear in the stationary pad to the minimum nominal clearance. This happens sometimes with the CB750F0/1 rear caliper: it has happened to me twice.

The OEM spec for the pad-to-rotor clearance for the non-powered pad is 0.1mm/0.004", if you have an adjuster for it. I usually set them a bit tighter, like 0.05mm/0.002" instead, as many of the rotors are not dead flat anymore, and this tighter adjustment will reduce the free-play in the brake lever.

I have had to 'reduce' the thickness of several brands of the pads (static pad side) in the past.

Thanks for the help, and that's exactly what I did. Put them on the belt sander until they were a good width, worked like a charm. I had this in my mind but didn't know if it was something I should do. But the brakes work perfectly fine now. Thanks