Topic: 72 750 front disc upgrade not helping

[gmet]

Thanks for the bedding info. 
Does someone make a bracket to fit the V65 caliper to a fork leg such as my72?

[HondaMan]

Maybe a hint here:
(A LONG time ago (when the CB750 was still King of the Road), it was popular to have the disc 'lightened' with holes like yours, and Cycle magazine (et al) was filled with machinist ads to have your disc drilled. Trouble was, if the holes were drilled and then heavily beveled (and not just the edges of the holes broken with a very light touch) the brakes LOST stopping power. It became common to have the holes just drilled (maybe in some pattern or another) and then the first set of brake pads were 'sacrificed' to quickly break in the disc. This worked well, but of course, Honda's pads were available everywhere then. Sometimes the 'fix' was to add the 2nd disc, but that's another topic...

(Fast forward again in my Wayback machine...)

Modern disc-hole-drillers are mighty proud of what their CNC can do for their egos, but I don't believe the physics have changed: I have noticed on a couple of cafe'd 750s that have resided temporarily in my garage that their widely-beveled-holed front disc (or discs) can't hold a candle to my almost-stock single disc (750K2), still OEM except for a straight(ish) shallow groove I added on each side to sipe away water while riding in WA State one soggy summer.

If truing the pads don't solve this one (because yours are barely contacting the disc pads' surfaces), maybe consider getting a new, sharp countersink and touching the holes to raise a slight edge on them at their tops? This edge will quickly wear off, but will also true the pads to the disc face(s) where it counts.

[scottly]

Ok, I pulled the front wheel off and checked the rotor to see if it was on the carrier in the proper position and the way its machined makes it only fit one way so my offset has not changed.  I pulled the caliper apart, recleaned the bore, sanded down the paint on the sides of the puck backing plate so it slides freely in the bore, added a touch of grease on the sides of the bore. Beveled the edges of both pucks and finally resanded them on a belt sander with 180 grit. 
Took it for a spin and no change whatsoever.  You have to grab a huge fistful of lever to lock it on grass!
The piston and pad moves easily in and out of the bore but I pulled it apart after I got back and noticed that theres only a small amount of contact in the very middle of both pucks.

With the rotor mounted with the offset the wrong way like you have, the back side of the rotor is closer to the wheel than stock. You may need to put shims under the caliper bracket where it bolts to the fork leg to space the caliper away from the fork and towards the wheel. One way to check this is to loosen the three bolts, then apply the brake. The caliper squeezing down on the rotor will try to align itself. You may have to remove or at least move the fender brace out of the way while doing this, as the brace is bolted to bosses on the caliper bracket on your K2. And leave the damn adjuster spring and screw off until you figure this out. (I just plain leave them off. )
There is supposed to be a pin that threads into the hole in the piston-side pad; it fits into a groove in the caliper body. Hopefully you still have the stock pad you can use the pin from.
Like David said, you want to sand the pads on a flat surface, like a piece of glass or metal plate. Hold the pad with your finger tips, and move it in a figure 8 pattern.