Topic: CB750F Rear Master Cylinder WITHOUT White Plastic Reservoir?

[Ricky_Racer]

We've been trying to finish up a gorgeous 1975 CB750F, but the rear master circlip and washer are so heavily corroded that they're "welded" together. In going through the spares, I found an identical rear master (same everything) that has the reservoir molded into the base, so NO PLASTIC RESERVOIR. Both the old rusted master and the new one-piece master have 14(dia.) cast into the base and, other than the reservoir, appear to be twins. I grabbed a pic off the Web of what I'm talking about.

I'm hoping that the OEM rebuild kit we're going to use will fit the new, more unusual, rear master cylinder. Can any of you gurus on the board shed some light on what the new master originally fitted? Could it be Japanese domestic? Any enlightenment would be great. Thanks! RR

[KRONUS0100]

thats 1975 and 1976 750F rear master

[Jerry Rxman Griffin aka MuthaF'er]

At  CB750F-1010154 Honda switched from the nylon reservoir to a one piece all aluminum reservoir which carried over to '76. The early Gold Wing reservoirs look almost identical except they do not have the cast in stop for the brake line to keep it from rotating loose and exit straight out without the 90 degree exit. They also have a 'restrictor' at the bottom of the thread hole presumably to keep the rear from locking up (? - speculation on my part). The rebuild kit will work for either.

[Kickstart]

Interesting.. I always wondered about that.

I have four 75 CB750F's (well 3 and one parts bike).  Three of them have the plastic reservoir and one of them has the all aluminum reservoir.

[Ricky_Racer]

Very cool. Great answer, Jerry! I seldom work with "F" models so this had me stumped. Now I can relax about whether or not the rebuild kit will work. Thanks for your expertise! RR