Author Topic: Stopping front brake clunk (CB750)  (Read 4249 times)

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Offline Raul CB750K1

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Stopping front brake clunk (CB750)
« on: March 25, 2010, 12:31:29 pm »
The question has been dealt with here before: in the CB750, when you go over a bump, or apply the front brake, a "clunk" is heard. By shaking the caliper with the hand, it is possible to reproduce the sound. The reason is that there is a little play between the caliper holder and the bracket where it rotates.

Honda issued a technical bulletin back in the day. The solution was to shim the free play. There was two different washers -0.1 mm and 0.2 mm if memory serves me- and the procedure was to install either, both, whatever it takes to fill the tiny gap.

Long time ago I bought one of the washers -the other was not available- and was planning to do it when the time for brake pad change come. Well, my brake pads were not too worn out but I had to replace the front tire, long story short, let's change the pads now and save some time in the future at the expense of some brake pad remaining.


Sure enough, I couldn't remember where did I put the shim washer I bought! I searched and searched but couldn't find it. And I knew that there would be no better time to stop the clunk than now, because when the washer appears, I won't remove everything again to install it.


What I've done is to use one of the inexpensive feeler gauges I have. I have three or four sets, one of them is very good, with many thicknesses, but this one was cheap and had not many. I just checked until I found the one that fit better, then I cut it to size. Making a hole with the drill is almost impossible without destroying the thin sheet, and so I used one of those punches used to cut rubber or gasket paper. I know, a donut-shaped gasket is a much professional fix, but hey, I think I can live with this.



Offline SOHC4ever

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Re: Stopping front brake clunk (CB750)
« Reply #1 on: April 13, 2010, 04:51:41 pm »
Bloody great idea, Raul.

My Honda dealer can't or won't order these parts for me, so I'm going to have to do something similar.

I don't suppose that you know the inside diameter on those washers, huh? That klunk is driving me mad, and it's brakepad time.

I'd like, though, to have the washers (or "washers") ready to put in before I start taking the brakes apart.

Offline Johnie

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Re: Stopping front brake clunk (CB750)
« Reply #2 on: April 13, 2010, 04:59:44 pm »
Excellent Raul...I hear it on my KO too. Saw the TB on it, but the size washer it said to install was to big for mine. So I just tightened the screw a bit and it was better. I should do this sometime. I did put a little Teflon tape on the shaft and then carefully pushed that in trying not to mess up the tape with those rubber washers. The tape just took up some of the play for me and made it quiter. I forgot who it was on this board made himself a brass bushing for the shaft which worked too.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive
2000 1500 SE Wing (wife's pearl white bike)
1970 Chevy Chevelle SS396 - Cortez Silver

Oshkosh, WI  USA

Offline SOHC4ever

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Re: Stopping front brake clunk (CB750)
« Reply #3 on: July 03, 2010, 10:51:41 pm »
I just got around to taking this apart.

How did you manage to get the shaft out of the bracket? I couldn't get it to budge for nothin'!

You could say that that shaft's a bad mother...

Offline Johnie

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Re: Stopping front brake clunk (CB750)
« Reply #4 on: July 04, 2010, 05:55:52 am »
That pin came out pretty easy for me once I removed the entire unit from the bike. Took out the cotter and just tapped it through.
Did you guys just notice one of these NOS brackets and pin went for $243 on eBay. Gosh, this feeler gauge fix or the brass washer sounds so appealing now.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive
2000 1500 SE Wing (wife's pearl white bike)
1970 Chevy Chevelle SS396 - Cortez Silver

Oshkosh, WI  USA