Alloy brake reservoirs

[andy120t]

I'm trying to establish what master cylinder / reservoir I've got....this would be easier if I posted a piccie but I don't have a working camera here so:

Mine has the cylindrical reservoir which all the early CB500/550's seem to have, but the reservoir is quite deep (about 2 inches) and made of plastic.

For the look I'm striving for on my rebuild I need the all metal / alloy reservoir that I've seen on other bikes. These ones are also only about an inch deep.

So the questions are:
- what bike is the deep, plastic reservoir from?
- which model are the shallow, alloy reservoirs from?
...(and does anyone have a spare shallow, alloy one they wish to part with..!)

Thanks!
Andy

[Bryanj]

Plastic round was GL1000, which you need for twin discs. If i can find the box of bits i will have a spare normal one needing seal kit somewhere

[andy120t]

- I'll be running twin discs so maybe I need to stick with the one I have?  Any idea what size master cylinder is in the alloy one?

NB - certainly interested in your spare one; I'm running GPz400 calipers so even one of these should have pretty solid stopping power & I really need to have clean, minimalist handlebars.

[K2-K6]

Think the reason for having a taller / greater capacity reservoir is to cope with two lots of pad wear between scheduled service intervals i.e. with no attenttion for whatever amount of miles between the bike being inspected it wouldn't run the fluid too low. Looks like they were being a bit generous so you should have no issues if you check it realistically with a smaller cpacity.

I'd guess at more of an issue if you were to tip one down away from the outlet significantly, although there is usually a rubber baffle in there it may not cope with lowered fluid and adverse angle.

Newer stuff runs some very small reservoirs and big calipers but they are arranged normally so the fluid can't help but fill the operating cylinder easily.

Didn't somebody fit a system that had a cable from the lever to a remote MS mounted on the frame (may have been BMW K series) that would give a very clean look.

[Bryanj]

Twin disc has bigger bore to push more fluid for 2 pistons, standard single caliper master will always feel "Soggy" for want of a better word

[matthewmosse]

bmw r80 rt I have in bits used the cable operated master cylinder under the tank. Worked fine, most owners these days switch to the brembo conventional system though, saves lubing a cable

[andy120t]

Intersting thoughts - I didn't know any production bikes ran that system, I'll have to have a look at a BMW.

I've been thinking of a cable set-up during the build & coincidentally I was looking at the space under the tank / around the coils just last night to see if there was space to put my existing master cylinder under there. A cable only would look very clean and there seems to be room under there, even more so if I could squeeze both coils onto one side of the frame. I thought it would be possible to run a pivot arm (eg a cut down brake lever) to activate the brakes via cable.