500/550/750/GL1000front Hub Question

[AshimotoK0]

Selling a spare front 500/750 hub I have,  to a forum member

I have three front hubs  ..one is for my K0 and different than 500/ 750k1 onwards . But of the two I have left one has flats for speedo one doesn't. Problem is I don't know which one I need to keep for my 500K0 as I have foolishly mixed em up. Anyone know which bike did not have the flats on it for the speedo drive and are they identical apart from that ?

checked loads of parts lists 750k's F's, CB500's,CB550's inc K3's, Goldwings, even CB500T & CB450's but they all have basically the CB750K1 part no . listed. was there a 'bonded' speedometer gearbox drive plate?

Or are the flats merely a throwback to the 750K0/sandcast?

[Johnwebley]

my K2 500 has the flats on the speedo drive side,

 it proved useful when I fitted a second disc,and had to get another drive plate

[Bryanj]

It was the late 750's and maybe the 550 K3(not sure) that did not have the flats. All early 750 and 500 did have

[AshimotoK0]

It was the late 750's and maybe the 550 K3(not sure) that did not have the flats. All early 750 and 500 did have

Checked all of part numbers for later bikes though Bryan and same as 750K1    44601-300-040  , even the 550K3 . The CB750K7 is a totally different design and of course F2 is Comstar. Presume hub is OK to use without the flats anyway?

Also checked the CB550F variants and that's given as the one with flats.

[Bryanj]

Far as I remember its one of the few times the part number did not change, nor the picture in the parts book, the only one that needs the flats is the early 750 that has the drive plate locating on them and the chrome trim with no indentations for the later drive, or if you want to fit twin discs easier!

[AshimotoK0]

Far as I remember its one of the few times the part number did not change, nor the picture in the parts book, the only one that needs the flats is the early 750 that has the drive plate locating on them and the chrome trim with no indentations for the later drive, or if you want to fit twin discs easier!

Guess it was one less machining operation to do Bryan.

For info here is the Service Bulletin no. 26.. My K0 had a K1 wheel on it so this bulletin was very informative at the time ( probably originated from you anyway that SB) The disc is different on the K0 too.

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