Master Cylinder replacements?

[Guest]

Hi folks!
The front brake of my -82 GS1100e is not currently up to it's best performance.
I've rebuilt the calipers, mounted braided ss lines and removed the anti dive units, but the leveler is still so soft for my liking.

First of all I don't think this is due to air in the system, I've had my share of troubles bleeding the system from dry, and think I've managed that part by searching this forum for tips. The leveler is not "spongy", it just has to much travel for my liking. It nearly reaches the handlebars before it stops moving from pressure build up. On my 450 the movement before it becomes hard is no more than 10 mm (3/8in).

The po said that the master cylinder came from "another bike", presumably a matching Suzuki. It looks like the stock unit, but ordering up a repair kit, I encountered the same problem as others have before me - it didn't fit.

Now to the real issue:

Someone said I could use a master from a 90's ZX9 - does anybody have any information on this? pics? how about mirror mounting with this set up?
In short; I need info on this mod. as it now seems very tempting to try out.

Thank you for you're indulgence.
-blo

[txironhead]

You can use any metric master cylinder as long as it meets two requirements: It fits the handlebar (1" or 7/8") and it came off of a bike with the same number of calipers. I'm running a M/C off of a newer Ninja, not only does it have a newer, better brake switch and more modern design, it bolted right up and the brake lever is adjustable. If you go with a Kawasaki M/C, you'll need to use the Kawasaki master cylinder banjo bolt, other than that it's a direct bolt-on. All you have to do to hook up the new brake switch is cut the old wires right at the switch and install two connectors that fit the new switch. Doesn't even matter which way they go. And finding reliable rebuild kits for newer M/Cs is much easier. Just remember what it came off of in case you ever need to rebuild it.

BTW, I got the Ninja M/C, brake lines and both six-piston calipers off of Ebay for $9 plus shipping.

[blo]

Thanks txironhead!

That was the kind of info I was after.

What did you do for mirror mounts? I don't think Kawa use them on the brake assembly like Suki does.

-blo

[tfb]

GPz900 -- has all you want, inc. the mirror mount. Works a treat on my old Katana 1100.

[Nessism]

Dual disc master cylinders have a larger diameter bore than singles. Maybe when yours was replaced they used one for a single front disc brake system? Droping the diameter makes the level spongy but reduces hand effort.

Not sure about a 1100 but the manual on my 550 calls for a 14mm master cylinder bore for a single front disc and 16mm for dual. You might want to match the original size if you go with something that is not stock. The factory manuals have the specs.

Edit: one more thing, using stainless/teflon brake lines really firms up the lever since they do not expand with pressure. Nice upgrade. You can build your own from parts (cheaper) or purchase a complete kit (faster/easier).

[txironhead]

Can't say for sure about all Kawi M/Cs, but the only difference in mirror mounts is that the Ninja mount is maybe 1/2" taller than the GS clutch mount.

[Jaguarjoe]

You can build your own from parts (cheaper)

How do you do that?

[AOD]

It fits the handlebar (1" or 7/8") and it came off of a bike with the same number of calipers.

This is true to some degree. You need to size the master cylinder with regard to the piston size in the caliper. The 1100 should have a 7/8 master cylinder bore.

See and read about it here: http://www.vintagebrake.com/mastercylinder.htm

I thought about replacing my 1100 to give me MORE travel and feel. With the stainless lines and a rebuilt master cylinder miy lever does not even go back far enough to turn the brake light on.

My assumption is the person who put the replacement master on your bike used the wrong size and that's why you have too much lever pull.

~Adam

[Nessism]

How do you do that?

http://www.anplumbing.com/shop/

http://bwringer.com/gs/brakelines.html

[blo]

Wow!
I love this place (that's including you folks)!

One small question, and I get enough info to really dig into my braking system.
The neighbors are going to see someone going at his bike with vernier calipers tonight.
From what I read here, I'm almost certain the PO got the wrong master cylinder.

Again, thank you

[txironhead]

Keep in mind that most Ebay sellers won't want to tear apart their master cylinders to tell you what bore theirs is, so you may have to do some side research. Say you find a good deal on a Yamaha M/C, you should be able to find out what the bore is somewhere on the web.

I've had three bikes that didn't have factory M/Cs on them, nor even one from the same manufacturer. I had a Yamaha on my Shadow and I had a Harley aftermarket (think it was Mustang) chrome one on my CB750 chopper. I've never had a problem as long as I made sure it was made for the same number of calipers. Finding the exact bore is probably good insurance, though. If you're picky about lever travel, I highly recommend finding one from a Ninja, that adjustable lever is really nice and the sight hole faces the rider so you can view it while riding, which is a nice touch. Plus, it looks much nicer than the factory one.