79 550 front master cyl?

[Pendulum]

My front master cylinder is leaking, and the fluids all nasty so I want to rebuild the caliper and replace the MC. If the budget allows, I'll do stainless lines. Probably just going to do new rubber lines for now though...

My question is, what BMCs can I use? I'd like to upgrade to something with a better look to it.

[ChicagoBob]

Anything with a similar bore. Check out the selection at Mike's XS. I'm using their #08-262 (12.9 mm bore), but several of the others would also work. See pic below, and in my album.

[Pendulum]

Thanks Bob, that's exactly the info I needed. Now that I have the bore, I can search around. I'm assuming the brake line banjo bolt is 10x1.25? I haven't measured yet.

[Rover]

Anything with a similar bore. Check out the selection at Mike's XS. I'm using their #08-262 (12.9 mm bore), but several of the others would also work. See pic below, and in my album.

Did you have to do anything special with the brake switch?

[Pendulum]

Even better... Looks like the Mixes XS unit comes with the banjo bolt, and the switch. I needed a new switch anyway.

[Pendulum]

Ordered! Looks like I need to get my caliper rebuild kit and new lines picked out tonight. Thanks again Bob.

[cowboyup3371]

To be honest you won't pay much more for the new stainless lines and they'll give a better feel than the rubber ones, IMO

[Nessism]

The proper size master for a single disc front brake is 14mm.

[Pendulum]

To be honest you won't pay much more for the new stainless lines and they'll give a better feel than the rubber ones, IMO

Stainless, clear jacket, gold collars is my plan. I need to get some final measurements taken tonight, but I'm going to replace the hard line on the swing arm with 1 single line all the way to the rear caliper, and also convert the front to a single line.

The proper size master for a single disc front brake is 14mm.

I wish I'd seen your threads, and this post, sooner. I already received my new master cylinder, with a 12.9mm bore. I don't ride hard, and I'll be rebuilding the caliper and adding new stainless lines + pads. Will that 1.1mm difference be a big deal?

[ChicagoBob]

The one with the 12.9mm works fine for me, on my single-disk GS550, and that brake light switch is much more reliable than the stock unit.

[snicrep5]

you better be sure you order correctly from mikes xs. he absolutely will not refund or exchange parts once ordered. He will not answer any emails or phone calls (if there is a number). I tried to email him before ordering mixture screws. didnt get an answer, but being compulsive, i ordered anyway. He does state that he doesnt refund or return in the disclaimer. thank goodness everyone is not like him.
btw im using a 97 gs500 master cyl on my gs1100, works great.

[Pendulum]

Thanks for the heads up... His website is 'meh' at best, but thanks to everyone here I got what I needed. It's been sitting in my closet for a while now... I've already installed the clutch lever I ordered. Now it's time to for the brakes. I need to figure out what to order for the front line.