Topic: more silly questions ie rear disc brakes

[Don R]

  For anyone in the know about F rear disc brakes, do you prefer the twin piston F0/1 or the single piston F2/3? I've parted out one of each and am curious.
  I'm aware that many guys think any disc on the rear is overkill.

[newday777]

I haven't run either as I've always had the K drums over the years but interested. The 2 pot will definitely grab better than the single pot.
I've been thinking of converting over to disc on a build as I have a couple sets of Morris Mags, rear disc brakes with Lockheed 2 pot calipers and also Pagehiln masters w/rearsets for the Seeley frames(will require frame mods,  remove the triangle frame and add bungs to mount the Seeley rearsets to the K frame like the Seeley frame had) or make a matching Tickle rearset half as I only have one side for the K frame. I bought these NOS off the shelf parts from a long time friend who was the US importer of Seeley frame kits(no frames left unfortunately.....). I do have a couple extra clean K model frames to work with for this build.

[Bankerdanny]

I wasn't able to use the OEM setup on my F1 and ended up installing an F2/3 single piston. The '75 GL1000 semi-roller I just picked up came with what looks like a good rear brake setup that I could swap over if I wanted (assuming I could find the correct replacement rear hose I have in my parts stash somewhere.

Performance wise, the twin piston F0/F1 caliper should be superior to the single piston F2/3, but as we all know the rear brakes don't actually do that much work compared to the fronts, so I suspect that on the street it doesn't really matter.

[Jerry Rxman Griffin aka MuthaF'er]

The stock F twin piston rear is overkill and can too easily lock up the rear on an unsuspecting rider and make the rear unstable.

[Don R]

 Thanks, I was thinking someone said the F2 single piston was their preferred choice over the F1 double.
  I started this 750 business by dragging home an F0 frame but soon discovered it was wrecked and sort of repaired.  I saved the swingarm wheels and brakes and recently did the same from a junkyard F2.

[Tracksnblades1]

You’ll have two piston orings to back off each of their pads..
Opposed pistons won’t require adjustments as the pads wear…
If your going with a rear set you won’t need the mile long brake pedal 😜

[Shtonecb500]

I prefer the F0 look over the single piston f2-3 models. I havent installed any of the rear disc brake set ups on my bike yet either.  Ive locked up my wheel with rear drum brake many, many times. My brake stay has also come off and almost killed me on the freeway....I rather run the disc brake on the back and not have it adjusted so tight ever...at least when and if that fails it just doesnt grab the disc.

Edit: I know the brake failure I experienced was 100% rider error.

[seanbarney41]

I think the F0 caliper is a bit heavier.  And I really feel like the F0 2 piston caliper and master cylinder combo actually results in a weaker rear brake than the single piston f2.  They both require more force to lock up than a drum rear, given a rear tire that has decent grip.  Really, neither have any kind of decisive advantage.  Use the one you like.  Brake stay failure can get real nasty real fast so ALWAYS make sure your hardware is proper.  A friend of mine had a brake stay fail, locked the rear wheel and jammed the pedal back against his foot so hard it broke his foot on a cb400f.

[Shtonecb500]

I think the F0 caliper is a bit heavier.  And I really feel like the F0 2 piston caliper and master cylinder combo actually results in a weaker rear brake than the single piston f2.  They both require more force to lock up than a drum rear, given a rear tire that has decent grip.  Really, neither have any kind of decisive advantage.  Use the one you like.  Brake stay failure can get real nasty real fast so ALWAYS make sure your hardware is proper.  A friend of mine had a brake stay fail, locked the rear wheel and jammed the pedal back against his foot so hard it broke his foot on a cb400f.

Mine broke off and jammed through my mudguard and into my seat. I’m very lucky.

[Don R]

 
  Thanks for the good discussion.
  I'm deciding how to build the turbo bike, its raked 10* extra, will be low with the exhaust around the side and have a fat drag tire on the back.