New to CB400 four and new here! Front brake improvement?

[Trigger]

Ah! OK...  I'm working/hoping to get adequate performance from the OEM but am wanting alternatives in case I can't get sufficient performance. 

FWIW, my CB400 is going to be my normal rider, not a weekend or "special event" bike.  Therefore, as much as I would like to retain the OEM gear/appearance, It's less important than being able to STOP.

It all depends on what brake parts are old and worn out. Easy to do a full overhaul with, Stainless steel brake piston, new OEM piston seal, new brake lines and used a DSS aftermarket master cylinder or refurbish your original with a new service kit. You can always have the disc drilled for extra grip 
Or if you want a very good braking system, be prepared to spend £££ 

[Laverdaroo]

A CBR 600 master cylinder will be for a double disc and not for a 400/4 single disc. 

Yup, fits straight on and works fine with no immediate on/off application. No faults found and works perfectly. Really happy with the install and did so after much research from other sites and expertise elseware. Cheap option, dead easy to fit, the lot.
Recommended


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[Trigger]

As a new member you will soon find over members commenting on your post telling you that their bike has the best braking system but, they may or maybe not taking about a CB400/4 

[Laverdaroo]

I'm going with the CB1300 MC Mike, it has a mirror mount and a front brake light switch if you ever need to remove the one on the bottom yoke. Look identical to the CBR600 one although I can't see any mirror mount on Roos pic.

The Long Haired General wanted bar end mirrors which aren’t in at the min as it’s being fiddled with and sick of catching my pockets on it walking around the shop.


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[Laverdaroo]

Yup, as it’s on a 409/4 thread, I was referring to our 400/4


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[Mikep328]

OK!  So if I understand correctly, the mid '90s CBR 600 MC will work with the OEM caliper/rotor on a 1976 CB400 four.   Right?

[Trigger]

There is no quick fix on a braking system .
Roo has forgot to mention that he doesn't have standard handle bar switches and his bike is £££ modified   

[robvangulik]

The CBR600 master is most likely a half inch or 12,7 mm, which is fine for a single 38mm piston caliper.
On all Honda masters the piston diameter is cast on the outside, most often facing the handlebars.

[Trigger]

The CBR600 master is most likely a half inch or 12,7 mm, which is fine for a single 38mm piston caliper.
On all Honda masters the piston diameter is cast on the outside, most often facing the handlebars.

My up to date tech data Honda book only shows the spec for a CBR600 from 1999 and the size is 13.958 to 14.000 mm 

[robvangulik]

I've put a 12,7mm 1994 CBR600 master on my CBR1000F.....was 5/8 inch.

[Laverdaroo]

The photo I put up shows how modified it is. You can only fit corresponding levers with the master cylinder and it cost less than £80 for the cylinder, repair kit, paint AND levers. A good mod, cheap & works.
They fit the STANDARD bars that I have on the 400 so a quick fit also. Not the first to do this swap, loads have done it to sort the issue of crap anchors.
The master cylinder is a 93-98 CBR600, if you want the link to the levers let me know.
Happy to help


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[Mikep328]

Had a revelation in the middle of the night re the brakes...(note that a "revelation" for me might be common knowledge to everyone else...)

It seem to me that by design the front brake is only half of a brake.  The fixed pad cannot move and it does not touch the brake rotor if properly adjusted.  SO...when the front brake is actuated, the piston moves ONE brake pad against one side of the rotor.  It is the ONLY brake pad applying pressure to the rotor until your hand applies enough pressure for that pad to warp/bend the rotor far enough to engage the fixed pad.  Frankly, this makes no sense to me, the rotor has to literally be bent into contact with the opposing pad before pressure is applied to both sides of the rotor.

Without a floating rotor, I don't see how such a brake can work effectively under any conditions.  It seems to me that the only way to get a GOOD front brake is to either have a floating rotor with the current caliper or a replacement dual piston caliper. 

Or am I missing something obvious here about the brake construction/operation?

[Bryanj]

You are missing a lot!
The "fixed" pad is mounted to the alloy bracket that pivots, or at least it should do, on the steel pin held by 2 small and one big bolt. The 2 small bolts hold an alloy bracket that SHOULD slide off the pin.
So when you aply the brake the piston moves out till pad touches rotor, then further movement brings the other pad to touch as the arm pivots.
If the clearance on "fixed" pad is too much the lever moves a long way, if too little the pad rubs.

The only thing that retracts the piston is the twist in the rubber seal which is why, unless the seal groove is super clean, the brake can drag and a dremel brush WILL NOT clean the groove, it just polishes the crud. You need a dental type pick and patiencs

[K2-K6]

Adding to Bryan's information, all single piston  caliper have method to move the caliper assembly during brake pressure to pinch the static disc and make effective braking.

There's less swing  calipers around nowadays, but many bike and car use sliding pins to move with pistons on one side only..

Floating disc, these are almost entirely to deal with control of disc expansion through heat range where used to avoid the disc going wavy and not to accommodate caliper geometry. 

[Mikep328]

Ah, OK!  Thanks!!!  Makes perfect and obvious sense and I clearly misunderstood how it works.  In my (rather thin) defense, we are in Italy on holiday at the moment and I was picturing the brake in my mind as opposed to looking at/examining its function it on the bike!    Also, this is the first such brake (without opposing pistons) I have ever worked on though I apparently had them on several bikes years ago - Honda CB550, CB750.  But I never worked on those brakes or felt that they were inadequate.