Best budget brake setup?

GuitarGuy1996

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Hey guys! So I've got a 79 xs750 that I've cafe's out and am just about done with! One of the last things I have to do is figure out the front brakes. They're bleed many times over, new pads, the calipers aren't locked up, but the brakes barely do anything if anything at all. When I pull the brake lever, I can feel the calipers moving a tad so I know it's working, just not enough. I think the culprit is the Amazon ASV levers and master cylinder I got for it. I'm running the same thing on my dirtbike and it works great but that's a single disk. I don't think it can push enough fluid for a dual disk. Any swap ideas? I'd like to keep the lever itself there and swap for a bigger master cylinder if at all possible.
 

arcticXS

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15-16 mm main cylinder piston should help. What do you currently have? I have to admit I get a bit nervous when I hear about non- brand aftermarket brake components. I believe "coffin reservoir" type Brembo master cylinders cost no more than maybe 120-140 dollars. That is cheap compared to US hospital bills ... Anyway, what exact calipers does your bike have? Number of pistons, and piston diameter please?
This info will enable us to find a suitable size MC for you.
 

arcticXS

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Other good aftermarket master cylinders are Grimeca and Magura. And if course OEM master cylinders from Japanese and Italian bikes can be used as well, both new and used.
 

GuitarGuy1996

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I'd have to take it apart to get the exact specs but they look to be factory calipers and lines. 1 piston per caliper. I'm sure the old lines don't help any either.
 

arcticXS

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Ok, here goes, again: 70's bikes had crappy rubber brake hoses that couldn't take high pressures without expanding. And mostly way too large master cylinders. So if you want better brakes, but still would like to keep stock discs and calipers, a smaller master cylinder, modern hoses and good pads can give pretty good results. Read this:
http://www.vintagebrake.com/mastercylinder.htm
 

arcticXS

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Yeah and I've been wondering about those brake hoses too. I can feel them expand when I hit the brakes.
Yes, and when you fit a correctly sized master cylinder (i.e. most likely smaller than the one you have), then the pressure will be even higher. So new hoses is required in any case.
I suspect the calipers may be the same as 77 onwards XS 650, if so they are 38 mm single piston. Then the table from Vintage Brake suggests a 14 mm master cylinder for 2 x 38 mm piston ( 2 single piston calipers)
 
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