Author Topic: Brake disc question  (Read 811 times)

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Offline czakky

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Brake disc question
« on: February 21, 2022, 09:13:47 AM »
Hello, sometimes lurker here. I’ve got a question about a wheel that came with an old race bike (not a Honda) I’m restoring. It came with a dual disc setup that I believe is a modified CB750 hub/discs and calipers.
I’m curious if someone could help with identifying the parts?

The rim is an Akront 18” 40 spoke. That’s all I know but it looks like a CB750.

Thanks for any help. I’m going to try to sell these parts.

Online BenelliSEI

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Re: Brake disc question
« Reply #1 on: February 21, 2022, 09:34:02 AM »
Definitely Honda cb750 hub, brake rotors and calipers. The swivel brackets are not (or heavily modified). The disc is usually held on with 6 through bolts, nuts and lock tabs. Yours appears to be using the roll pins as centring drive lugs and through two bolts to keep it all together? That means the hub and discs have been modified to suit each other. They could be used on a cb750 as a complete unit, but are not longer interchangeable with standard parts. With that rim, would look good on a modified bike. That’s my opinion, be interesting to see what others suggest......
« Last Edit: February 21, 2022, 09:36:07 AM by BenelliSEI »

Offline czakky

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Re: Brake disc question
« Reply #2 on: February 21, 2022, 10:21:51 AM »
Thanks for the info Benelli, bummer about the calipers…

Offline seanbarney41

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Re: Brake disc question
« Reply #3 on: February 21, 2022, 12:08:57 PM »
Can't figure why anyone would use those caliper brackets?...What forks were they mounted to?  Pictures?
If it works good, it looks good...

Online BenelliSEI

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Re: Brake disc question
« Reply #4 on: February 21, 2022, 01:02:57 PM »
Thanks for the info Benelli, bummer about the calipers…

To be clear..... Calipers look std. brackets are fabricated.

Offline czakky

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Re: Brake disc question
« Reply #5 on: February 21, 2022, 01:18:32 PM »
Can't figure why anyone would use those caliper brackets?...What forks were they mounted to?  Pictures?
Guzzi V7 Sport. Originally a 4ls drum, so it was a definite performance upgrade. The forks were fabri-cobbled a bit.
Thanks for the info Benelli, bummer about the calipers…

To be clear..... Calipers look std. brackets are fabricated.

I see…

Any idea what a “I want to get rid of this quick” price would be?


Offline seanbarney41

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Re: Brake disc question
« Reply #6 on: February 21, 2022, 01:41:27 PM »
From what I can see, everything should be fully useable on a cb750 except the caliper brackets, as long as those roll pins can come out and the hole has not been enlarged.  Check prices on ebay for similar condition parts and then realize that the higher asking prices "may be dreaming".  The only thing here that is particularly rare or desireable is that akront laced to a cb hub.  I would be glad to make you an offer on the wheel and rotors if you are located in the U.S.
If it works good, it looks good...

Offline czakky

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Re: Brake disc question
« Reply #7 on: February 21, 2022, 02:09:55 PM »
Yup, SW Wisconsin. Can ship.

Offline Medyo Bastos

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Re: Brake disc question
« Reply #8 on: February 21, 2022, 02:37:34 PM »
Too bad it isn’t a 19 or 21


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Offline Shtonecb500

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Re: Brake disc question
« Reply #9 on: February 23, 2022, 08:09:06 AM »
If Sean doesnt follow through on purchase Im next in line.
73/74'' CB500/550 resto-mod - sold
75' 750f 91' cbr f2 swap cafe - mock up
74' 750 chopper hardtail - complete - sold
74' CB750/836kit - Black mix & match - daily rider - always tweaking
71' cb500 K0 survivor - complete
71' K1 - CANDY GOLD/BROWN Winton kit - in process

Offline Stev-o

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Re: Brake disc question
« Reply #10 on: February 23, 2022, 09:50:37 AM »
I dont have a dog in this hunt, but how old is the tire?  If over 8 yrs, it is basically useless. 

Could be a very nice setup for someone.
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Online pekingduck

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Re: Brake disc question
« Reply #11 on: February 23, 2022, 12:07:28 PM »
Were the CB750 forks on the Guzzi, or were CB750-style pivots welded onto the Guzzi forks?  The Guzzi fork triple trees are narrower, which would explain having to offset the brackets outward.

I might also guess that to take the front wheel on and off, you might have to unbolt one or both of the discs to get them by the caliper pivots.  Hence the 2 bolts rather than 6 making for a relatively quick release.  The bolts may also have been left a little lose to promote a bit of "floating", primitive  style.

It should be noted that the spokes may not be fully engaging the nipples, unless they were over-threaded.  Internal threads on the nipple do not start at the top, but about 4mm below the top, so they are actually engaging less than is apparent.
« Last Edit: February 23, 2022, 12:20:47 PM by pekingduck »

Offline seanbarney41

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Re: Brake disc question
« Reply #12 on: February 23, 2022, 12:15:24 PM »
If Sean doesnt follow through on purchase Im next in line.
oops... kinda forgot about this.  I really don't have an immediate use for this stuff without a matching rear.  Shtone, get on in there!
If it works good, it looks good...

Offline czakky

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Re: Brake disc question
« Reply #13 on: February 24, 2022, 03:19:56 AM »
The tires are closer to 30yrs old… so yeah, useless.

They had the calipers mounted to the fender bosses. Stock Guzzi triples, forks, etc.

If somebody is interested shoot me a PM. Otherwise I might have a use for the rim.