Slimline Front master cylinder question???

[rustynail99]

hey guys, i have a '79 XS650 with single front brake and a mikes stainless steel brake line. my question is i am looking for a new master cylinder and i was looking into the slimline lightweight master cylinder from mikesxs but i just want to make sure it is going to offer enough stopping power. it has an 11mm bore, is this enough to run my single disc unit, i have not intentions of switching to a dual setup, so it only has to work for he single. has anyone else used this one? how was it?

thanks!

 

[KevC]

rustynail99
The ideal master cylinder bore size can be calculated depending on the piston size of your brake caliper & how many pistons there are.
There is a chart at Vintage Brakes HERE which works it all out for you.(read it well to get your head around it & calculate the best size)
There is plenty of discussion on this in the "tech section" under Brakes, Fazer blue spot caliper...... etc
An 11mm master cylinder worked out to be the ideal size for my fazer blue spot caliper so I doubt it will be right for a standard XS caliper
Kev

 

[Tech7]

Hi Rusty, that's the one I'm using. Works great. Only problem I had was getting the pads seated in. Took about 100 miles. It's all good now.

 

[rustynail99]

hey tech7 you use the slim line master cylinder brake lever? im showing my naivety here but what would the master cylinder have to do with that pads (this is probably a stupid question...) do you have a stock brake and caliper set up? it says the OEM one for a single disc set up is 13mm piston bore, and the slimline one is an 11mm bore. does that mean that i wouldnt have enough fluid for the brake to work?

 

[Tech7]

Yup, used the lever it came with. Then I got a new clutch lever and painted it black. Stock new front caliper. The master didn't have anything to do with the pads. All my stuff is new, so I was just saying that it took a little while for the pads to feel like they were grabbing good. Nothing to do with the hydraulics. Brakes have a good feel. I mean, it's still a 30 year old motorcycle, it ain't sportbike brakes. You'll have plenty of fluid in your master for the stock caliper. You ride yours yet? It's a lot like mine. I know a lotta guys don't like the hardtail, but there's just something about it that works for me. So raw and simple. No speedo, tach or signals to distract. Just you and the bike. It's a blast.

 

[rustynail99]

yea i have a hardtail as well but i havnt ridden it yet but i have sat on it a bunch! lol. my dad has a harley evo rigid that i ride all the time so im not new to the hardtail feel. ok tech im gonna go with the slimline because i love the way it looks, but if it doesnt work im comin after ya! lol. just kiddin man, if it doesnt work ill just sell it and try sometihng different, but i have confidence in your advice thanks for the replys

 

[gentlemanjim]

MMM from vintage brakes/650 central recommends an 11 mm master cylinder. Cost is $69.000

 

[rustynail99]

oh, excellent, i really trust his opinion. he really seems to know his stuff. now if only he would get some left and right VM34 carbs in!!!! lol. thanks guys