Topic: brake pads for my k-4 and unknown caliper year.

[fuzzybutt]

the caliper i've been running on the k4 was from a 75 750f it had a larger piston, however, the caliper when i pulled it apart to rebuild, the bore was in terrible shape, very pitted and scored. so........... i'm putting a k model caliper on, got a new piston and seal kit, new speed bleeder as well. the only thing i need now are brake pads. this caliper doesnt look like my other (also destroyed) k model caliper though. it has the same size bore and bleeder screw as well but the way the pads go in is different. with the destroyed k model caliper theres a slot where a screw in the pad rides but with this one theres a stress fit pin in the top of the bore . what IS this caliper from and does anyone maybe know where i can get the pads for it.

[bryanj]

Which way round bot the two bolts go and what heads are on them?

[fuzzybutt]

the bolts go from the outside of the fluid filled part of the caliper and thread into the backside. theyre 13 mm hex bolts. 8mm thread size

[cafe750]

If there was a picture of the other side of the caliper, it may help. I'm thinking it's a 550 caliper. If its similar to appearance as the F caliper you've been running, except the bolt spacing is different then its off of a 550.

If you were running the entire 750F brake assembly, you'll need the K brake arm and caliper to convert back to the latter caliper. The F and the K arms are different in thickness, so you cant use the "K" caliper on the "F" arm, and vice versa....

Hope this helps!

[fuzzybutt]

not only is the spacing different on the arm but the piston in the one i was using is about 4 or 5 mm larger. i do have the arm and all related stuff for it. more pics

[cafe750]

That'd be a CB550 caliper....

[fuzzybutt]

ahhhhhh ok. i THINK this is the one that was originally on the k6 750 i got 4 years ago. piston is the same size as in the 750 and the speed bleeder for the 750 works too. are the thicknesses of the arms also compatible with a 750 rotor? i hope?

[bryanj]

From memory thats the later 750 caliper from sometime after K4 till F1 and should use the same pads as the 500/550

[fuzzybutt]

ah so this might be the original k6 caliper then. cool

[cafe750]

I do know one thing, the late cb750 caliper and the cb550 caliper look verrry similar, but the 550 has narrower bolt spacing than the 750's calipers do...

[fuzzybutt]

this one has different bolt spacing from the 75 750f caliper that came off of the mootorcycle, around 8mm or so difference.

[Clyde]

I think that it is a 500/550 caliper. They use the same seal as the 750K(0-6), but look like a750F caliper. However I am not an expert on the 500/550 calipers
The 750K caliper changed in 77 when the K7 and then the K8, used the same caliper as the 75F/76F1. The F/F1/K7/K8 caliper uses a bigger piston/seal and different pads (~42mm versus ~38mm for the early . They have a 10mm hex headed bolt screwing in from the outside.
The early 750K caliper (apart from a change of colour) remained the same up to 76. The bolts go in from the inside and use an allen/socket head 10mm bolt.
With your forks, I would try to get another F/K7 caliper if you want slightly better braking. If you want originality look for a K3-K6 caliper (AND ARM as the thickness of the arm is differnt to the F)

[fuzzybutt]

well, this is a "bitsa" motorcycle. i call it my k4 because the frame is a 1974 model that i got from Jacks Cycle and Salvage in sanford Florida. the motor is a k6 front end unknown year but between a k3 and a k6, rear wheel is a k6 front wheel is a 75 750f.

[bryanj]

When i looked up the pads for the f1 the part came out the same as 360 which i know is the same size as the 500/550. Perhaps the material is different, i dont know, but they will physically fit