Anyone Fit GMA 4-Piston Calipers on a '79?

[ericfreeman]

I recently replaced the two single piston front calipers on my '78 Sportster with new GMA 4-piston calipers and the difference is remarkable. What was a poor stopping bike now has very good front brakes, still using the stock master cylinder as well. The GMA units bolt solidly to the front forks using a number of shims to get the proper rotor to pad spacing. Takes a little fiddling but is actually pretty easy.

This got me thinking about trying to fit these calipers to my '79 CBX. All I'd have to do is fabricate an aluminum mounting bracket that bolts to the calipers and forks, fit the necessary shims and plumb the brakes. I'm not sure how the stock M/C will handle the calipers but if my old Harley M/C works fine then the CBX might as well. I'm an engineer so designing/fabricating the bracket would not be an issue for me.

Curious if anyone else has done this or if everyone just fits later model forks with multiple piston calipers. I'm not interested in changing forks, wheels, rotors, etc., only the calipers for more clamping force. I'll be interested in your thoughts.

Eric

[Terry]

Any brake improvement is a good idea but the main (only) worry I'd have is the size of those tiny 35mm forks the Z models came with. Hell, even the 100+ pound heavier Prolinks only got a 4mm upgrade. I wonder how they'd stand up to really good braking forces? How much bigger are those Harley forks?

[ericfreeman]

Harley forks are same size as the CBX, 35mm.

Eric