What kind of front brake caliper assembly do I have?

[legitmw]

I was rebuilding the front brake for my 1976 Honda CB 750K and ordered a new piston, piston o ring, and brake pads for that model, but they are all too small. I did a little sanding on the outside of the caliper assembly and found "K5" stamped into it, but the 750 K5 should have the same brakes as the K6 right? So I'm thinking the front brake is from a different model.

My piston is 43mm in diameter, 34mm tall with what seems to be a cap on the piston, not sure if it comes off, but if it does then it's 29mm tall.

My piston is on the left and the correct K6 caliper is on the right (that one measures 38mm in diameter and 34mm tall)

Some sort of cap on top mine. Not sure if it comes off

Rubber washer that goes on top

Then the brake pad goes on top, most of the pad material was rotten and came apart trying to take all of it out of the caliper

Any idea what kind of piston and brake pads I need to be buying?

 

[VonYinzer]

Pic of the caliper?

 

[legitmw]

That would probably help.

Other side

Not sure if this means anything, but the old brake pads are not completely round, there are cut out parts that are flat as you can see in the last picture, the new ones I got are round.

 

[Rich Ard]

Looks to me to be a CB450 caliper

 

[legitmw]

I sent these pictures to the guy on ebay that I bought the piston from and he said it's off a 77-78 CB750K which is the same for 76-78 CB750A and the 75-76 CB750F. Looking at the diagrams he included, that seems to be correct.

 

[mydlyfkryzis]

Looks like this piston:

http://www.ebay.com/itm/Honda-CB-750K-750F-750A-75-78-Hondamatic-brake-caliper-piston-stainless-steel-/230921682204?pt=Motorcycles_Parts_Accessories&hash=item35c4013d1c&vxp=mtr

 

[legitmw]

That is the one! and that's actually the guy I first purchased the wrong one from and now he's exchanging it. Great seller if anyone sees anything in his store that you need. Crazy fast shipping too. Got here 2 days sooner than I was expecting.