Master cyl kit

[Excalibur]

I have this master cylinder which came with a billet Kennedy forward control set.

mc1.jpg

mc2.jpg

Cunningly I thought I'd simply pick up a new cup at a local brake shop. My plan was foiled when they said they did not stock it!!
Size 3/4".
This forward control set was originally fitted to an Evo, Softail I think? I have the whole thing except for the brake lever which I'm just about to fabricate.

Studying rear masters in general, I note there is 5/8", 11/16" and 3/4" sizes mentioned.
The piston is aluminum and everso slightly domed where the cup abuts. There is witness marking of the 6 holes in the cup rubber.
Which kit/s would actually work?
41762-58A I believe is 3/4" and would require omission of the line-pressure-valve.
42374-77 appears to be another 3/4" kit, made for disc brakes.
42374-82A is coming up as 5/8". Did they go smaller bore thru Evo?

My mission is to learn everything I can and be ready plus understand what I can get away with at a pinch. I will visit my Harley maverick, he may have something on the shelf. Bike is running now and close to 1st test ride. It would be a blow if I had to wait 2 weeks for a cup/kit to come out from the US. That would seem extreme. Does it seem odd that brake shop didn't have a cup ??

What else would be handy info the know re this situation?

Thanks for any help.

[RooDog]

3/4 or a .750 marked cups are common Harley sizes, but the two are slightly different in height. But either should work in your MC with the caliper you are using. All Shovelhead handlebar MCs, and the Lockheed iron ones use suitable internal rubber parts. As do some of the aluminum footbrake MCs. Why your "brake shop" cant help is beyond me, perhaps they are metric oriented, or only service cars who often use larger bore cylinders, but the why matters not, just the fact that they can't help is enough to trouble you, no?
....RooDog....

[Excalibur]

Thanks Roo, good info.

It was a great plan. That shop just recently sold me wheel cylinder cups off the shelf. So, it must be a sign of the times. Not enough demand so they don't restock. A purely commercial decision.

Anyway I found a workaround. On the shelf I had a rekitted cast iron MC so I burgled all the bits. I'll re-order a kit (or two). Yes, a reminder that it's going to get harder and harder to run this old iron..

Also I had a damaged MC that came with Ironhead Sportster stuff. Between all 3 MC's I noticed the difference in cup depth as you were saying.
I suppose the important thing is a cup retracts far enough to uncover the tiny bleed return hole.

[RooDog]

Thanks Roo, good info.
..... Between all 3 MC's I noticed the difference in cup depth as you were saying.
I suppose the important thing is a cup retracts far enough to uncover the tiny bleed return hole.

That is correct.....
....RD....