GT750 Master Cylinder Q

[Drewski]

My GT came with the smaller "single disc" master cylinder fitted and I'm wondering if it may be possible to get it bored out rather than search for a replacement. Can anyone confirm the size of the larger MC bore please? I'm presuming it's 5/8".
Also, if anyone has a stripped down "double disc" master cylinder, a photo like the one of mine below would really help



Cheers, Drew.

[Coyote]

.6248 / .6264 Lo and Hi. I used the smaller one on a double disc setup on my 550 cafe. Works like a charm. Even though the MC bore is smaller, that also translates to higher pressure sooner.. I really see no need for the larger bore. Externally, you can't tell one from the other. Ask jabcb how well it stops. He has the bike now. Maybe he will chime in.
There is a sticky post at the top of this section called 'general specs and info'. MC bore and piston sizes are in there.

[Drewski]

Daah...maybe I'll just get a repair kit and give it a try

[Drewski]

Just looking at cruzinimages repair kits....my MC is a Tokico one right? Is this the right kit? The seal looks a bit different to mine in the photo.

http://www.ebay.co.uk/itm/75-76-SUZUKI- ... 3a9a553374" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;"


Mine:

[Coyote]

Yes. Asco MC's were not used much before 76. Buy a genuine Suzuki rebuild kit. After all, your life depends on it. Your brakes are not an area where you want to cheap out.
I have rebuilt a couple of these. I don't recognize the tan piece next to the c-ring on the right

[jabcb]

I had wondered why the brake feel was so different between RedZone & my stock 75 GT750.

RedZone is fine with the smaller master cylinder.
I did not like the stock GT750 setup & switched to a Power Lever.
Also upgraded the GT750 to stainless steel brake lines & aftermarket pads.

Stainless brake lines & aftermarket pads are definitely a worthwhile upgrade.
A brake line shop can match up your stock lines with black lines that look correct but have a smaller OD.

I don’t push vintage bikes very hard. If you do, then perhaps you should read this before making a decision: http://www.vintagebrake.com/mastercylinder.htm

[Coyote]

yeah. The smaller MC made the brakes a little more 'touchy', but definitely works. Always felt to me like it could easily do an endo. You don't want to grab too much front brake on her. Sadly, the rear doesn't work nearly as well. I think it's a leverage thing. The front and rear are so different it takes some getting used to.