Topic: When did they stop using Bird Bath master cylinder caps ?

[754]

 I am talking about the concave top models, no writing on them.
I suspect at the end of K1 maybe..
 my partsbook goes to mid 71, and only shows 1 cap. Anyone know when they switched to flat top style? And did they make them in flat, without lettering ?

[Hinomaru]

Are you asking about the CB750 K model?

If so, that master cylinder cap when thru several part number changes:

KO-K1 (concave-unmarked) 45513-300-003

K2 (flat type-marked) 45513-341-671

K3 (flat type-marking change) 45513-341-770

K4-K6 (flat type-marking change) 45513-341-771

I’ve never seen a flat unmarked cap made by Honda for the 69-76 750K.

 

 

[754]

 Yes, and I suspected they changed at the K2.
 But, it was also used on the 450, and the 500

[bryanj]

I suspect that the ones without markings are because the label has been peeled off

[754]

 The writing cant peel off. I machine the tops and sides off, on the lathe sometimes..