Pro-Link front wheel shim.

[steve murdoch icoa #5322]

Just a question about the shim that sits behind the front brake rotors on the '81/'82.
It is part #12 on the schematic. https://www.ronayers.com/oemparts/a/hon ... ront-wheel
How thick is it? Is it a spacer or a damper? What is it made of?

[SteveG]

Hello Steve,
The parts fiche does list it as a damper. I have had them apart on some of my F bike comstars and found them missing. I have destroyed some while replacing rotors, and put the rotors on without them. They are about the same as a manila folder in thickness, and made out of paper gasket-like material. I have noticed no negatives when not using them.

Steve

[Larry Zimmer]

My 'guess' would be that they are/were related to brake squeal. Or, possibly, dampen brake 'shudder' related to rotor thickness variation and/or runout with those boat anchor rotors.

[steve murdoch icoa #5322]

Thanks Steve and Larry.
You both confirmed what i thought about the part and i too have destroyed when swapping rotors and not bothered replacing them.

What threw me off was this EBay auction with that shim part #.
They look like metal spacers.
https://www.ebay.com/itm/HONDA-CB750-CB ... ondition=4

[SteveG]

Your ebay link certainly does look like metal shims. Thick too! I wonder if the wheel they came off of had some 3rd party brake rotors that needed to be spaced out to work, so they manufactured the spacer.

Steve

[EMS]

I wear glasses/contacts, so I may not see correctly, but my parts list does not show a shim behind the rotor on any CBX. Neither early nor Prolink. As my parts lists are for "Rest-of-the-world", the shim may be U.S. only
The part sold on ebay is NOT a CBX part and the part-number listed describes a shim (paper) used on the Euro CB1100F (among others)
The parts list for my CB1100R shows a part shaped like 45128-445-630 ( which is listed as original for 1979-1981 CB750F DOHC) with the part-number 45128-MC7-000, Damping Shim.
It is supposed to be replaced when disassembled.

[steve murdoch icoa #5322]

Thanks for the info, Mike.
I figure the same as Steve that the ones on Ebay are spacers for either non-stock rotors, calipers or wheels.
With the spoke wheels on my '79 and the Euro Boomies on my '81 i have used similar items.

[daves79x]

I have a couple of sets of the thicker metal shims for front rotors, that came from some Honda of the era, but not the CBX. The 'shims' shown on the parts fiche are indeed just paper. Use them if intact, or remove them, no problem either way.

Dave