9/16" or 14.3MM CB750 MC to replace Brembo PS15 dice roll

sfcpiet said:
'Cos it says so on the underside... :rolleyes:

Almost all motorcycle M/Cs carry a cast marking denoting piston size, at least all Nissin and Tokico products I've worked with, which covers about 99.9% of all Japanese motorcycles. Most Brembo stuff is stamped.

Hydraulics are traditionally measured in imperial units. Brembo stuff that is marked 13mm is actually 12.7mm or 1/2", 14 is pretty exactly 9/16" and 15 actually turns out to be 15.8mm which is 5/8". Haven't yet measured 12mm Brembo pistons, but I'd risk a bet they're actually 7/16".

piet
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Aware of that, many (most?) do, but several I've owned don't. Maybe shady stuff, but the Nissin on the Norton is not marked, and it's a stock piece. Just lucky, I guess. Thanks!
 
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sfcpiet said:
Quentin,

Seems pivot/piston distance is universally around 24-25mm these days on axial M/Cs. The Yamaha M/C I mentioned previously was more like 28mm which compensated a great part of the longer travel of the 1/2" piston when paired with dual discs. The donor bike would have had a single disc with a single pot caliper, RD250LC iIrc.

piet
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Wonder also if the position of the lever pivot laterally relative to the contact point on the piston is different between various m/cyls?
 
I've mounted the knockoff CB750 9/16" MC, and it's very good. The feel is exactly how I like: good initial feel & bite, progressive, proper lever distance and free play, & strong like tractor. It's enough for me, low-tech and inexpensive, yet effective for my needs. Plus, it looks right, as I wanted. The bike is a lot more enjoyable to ride.

There was a slight issue: the adjuster joint area of the stock bars collided with the MC's body just enough so it didn't sit flush on the bar. I put a thin aluminum shim inside the front bar mount's curved recess to push the MC forward just a bit. It's quite secure & I'm OK with it. It would be cool to anodize the MC and the Brembo's cap & use them together, and mount the original lever, if possible. Someday, someway, maybe I'll modify it 🎸. Doubtful anyone will get my music reference!

Brake1.JPGBrake2.JPG
 
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gpzkat said:
There was a slight issue: the adjuster joint area of the stock bars collided with the MC's body just enough so it didn't sit flush on the bar. I put a thin aluminum shim inside the front bar mount's curved recess to push the MC forward just a bit. It's quite secure & I'm OK with it. It would be cool to anodize the MC and the Brembo's cap & use them together, and mount the original lever, if possible. Someday, someway, maybe I'll modify it 🎸. Doubtful anyone will get my music reference!

View attachment 108362View attachment 108363
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The factory did exactly the same to have the Brembo M/Cs clear the handlbar clamp of the RGS.

piet
 
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