Topic: front caliper comparo turned out to be more of a report -o

[Don R]

 I'm currently wondering if an F0,1- K7,8 center feed caliper would make more stopping power than a standard K caliper? Comparing on the same bike with the same rotor.
 I know the F piston is slightly larger than the K piston but the advertised swept area is the same. I'd assume from the increase in piston area there would be a slight increase in force applied to the pad.
 

[seanbarney41]

My F0 has dual drlled and thinned disks and a 1990's Kawi 14mm master cylinder and stops really good.  It's been a long time since I rode a F0/1 with stock brakes but I don't remember noticing much of a difference in stopping power from an early k..at least without using the rear disc too.

[BenelliSEI]

I'm currently wondering if an F0,1- K7,8 center feed caliper would make more stopping power than a standard K caliper? Comparing on the same bike with the same rotor.
 I know the F piston is slightly larger than the K piston but the advertised swept area is the same. I'd assume from the increase in piston area there would be a slight increase in force applied to the pad.

Don….. I’ve always felt my K8 has a better front brake than the other (older) cb750s. Just assumed it was “in my head”.

[Don R]

 I had considered doing an a-b test but it's raining and the differences in the pads would likely negate any information I got. I'll just swap it today. For long term mods I have a rotor ready to drill and rebuild parts on the way for a late double disc swap like the one my 76F had. That bike was impressive when stopping, I felt like in a bad situation, I had a way better chance of stopping than a stocker.
 
   I've lucked into finding some nice 750's since I sold that one, but I still miss it. I had recently retired and had bought a Sandcast that I wasn't sure I could afford. Turned out I might have been able to keep the F but selling it made it way easier to buy the Yamiya pipes and a few other parts for the Sandy.
  Later, I saw the F with new paint and an original muffler re-sell at Mecum for over twice what I sold it for. I recognized the drill pattern on the front rotor and the incorrect color I painted on the F-B side covers.

[scottly]

 I know the F piston is slightly larger than the K piston but the advertised swept area is the same.

The early F/late K calipers have a 42.8mm (actually 1-11/16") piston, compared to the earlier 38mm. The swept area is actually less, as the pads don't reach down as far on the rotor. The late pad is on the right in this pic.

[BenelliSEI]

Don….. I’ve only ever had one “F” and like you I still regret selling it! It did have excellent brakes.

[Don R]

 I know the F piston is slightly larger than the K piston but the advertised swept area is the same.

The early F/late K calipers have a 42.8mm (actually 1-11/16") piston, compared to the earlier 38mm. The swept area is actually less, as the pads don't reach down as far on the rotor. The late pad is on the right in this pic.

 My pads are all round, both k and early F. The two pin pads look like Late F double disc. I sold both of those F2 bikes I've owned without robbing any brakes or forks.
 The OD of the piston side pad has an o ring around it, I haven't seen that before, it's working but seems like that might not retract like the piston does.

[Don R]

  I didn't try to do a scientific comparison, but that bike is without a doubt the best stopping bike I own. It is probably a lucky case of great worn pad alignment and a set of experienced stock Honda pads. It has a stock master cylinder and a one piece direct to caliper braided brake line, it has some more lever travel, either caused by the larger piston of a dab of air still in the line.
  This reminds me of the double disc F when I scalloped the front tire while practicing emergency stops.

[Don R]

 For those investigating brakes in the other posts here, I used a caliper from an F0-1 or a K7-8 it was cleaned well with a new o ring inside, a good, not pitted stock piston, I sanded a mildly worn set of stock pads and chamfered the edges slightly. The master cylinder is standard and was working when I got it. The brake hose is one-piece braided hose direct to the caliper from the M/C.
  At this time, I need to remember the rear brake provides the brake lighting. I'll put a switch on it this winter when I re-wire the bike.
  The rear is the best set of used shoes I had, not corroded around the linings or loose and hand sanded to remove the glaze, I flap wheeled the Lester brake drum while it was spinning to clean it and give it some tooth. I plan to swap in a nice 750 hondamatic panel if it fits, it has a wear pointer on it.
 I no longer see the need to double disc this bike but might anyway just because it's a Hot Rod.
   
  I'll attempt some of these tips on my K0 gold bike because its front brake scared the sweet beejusus out of me a few weeks ago. I suspect fork oil got on the rotor when it was tied down on a trailer.