Rotor swap on '77 GS750E

[Guest]

I read somewhere that it was possible to swap the rotors from the '77 gs750 to later model gs750s. I purchased some 1980 rotors off ebay and have disassembled both wheels for the swap. Of course the '77 only has one rotor up front instead of two, but I noticed that the 1980 front rotor is thinner than the '77. Printed on the rotors it says "MIN. T.H. 4.5mm" and "MIN. T.H. 6mm". Is this a direct swap out or not? Will there be adjustment in the pads to accept the thinner rotors? Thanks for all your help!

[GS750cafe]

No input from anyone here?
I guess I'll build them up and see what happens...

[tkent02]

Interchangeable, except that the single brake rotors are larger diameter than the dual brake rotors. They are thinner too, but that doesn't matter.

[GS750cafe]

Thanks for the input Kent. So, because they are smaller in diameter, does that mean I need different calipers? Or can I just bolt the smaller rotors on?
Cheers!

[tkent02]

The calipers are the same, but the fork legs are different, the mounting holes are 10mm or so further up the fork legs to accommodate the bigger rotors. Do a search for brake upgrades, there are several different swaps people are doing. The original dual brakes can work OK if everything is perfect, brakes from a later GS are much better, or go with the twin pot Kawasaki calipers and CBR900 rotors, bring your braking into the '90s. There is no reason to ride a GS with unsafe brakes.

[GS750cafe]

Thanks for the input. My '77 GS has only a single front rotor that is solid, no holes for weight/cooling. I was hoping to just swap the front and rear rotors out with the 1980 rotors. I guess I'll see what I get and if that doesn't work I'll look into the Kawi/CBR conversion.

[tkent02]

Swapping rotors will fit, but it won't get you any better braking. The later caliper is an improvement, but dual brakes are the way to go. Kind of why every bike made since then has them.