74 Z1 900 New brake master cylinder has very little movement

Wookie58 wrote:

Nessism wrote:

Wookie58 wrote:

Nessism wrote:

The Z1 manual hosted here says the master bore should be 14mm.  Using a 5/8" bore master will result in increased hand effort and a very solid feeling lever.

Whilst I understand an extra 1.8mm on the bore size will displace more fluid so reduce "lever travel" and "feel" however given that fluid is still being displaced under pressure I don't understand how this translates into poor brake efficiency (the OP said that the brake works but stopping efficiency is poor ??) can anyone clarify ??
I would suggest before spending more money and digging too deep that you check the calliper sliders as previously suggested (it will take 10 mins and is free)

This link does a good job of explaining... www.vintagebrake.com/mastercylinder.htm

I put a 5/8" master on a bike that had a very spongy feeling front brake lever and the result was rock hard feel afterwards.  The brake feel was poor, though.  Wooden feeling, so to speak.




 

Nessism I get the change in lever action but when you fitted that 5/8 cylinder was the brake efficiency effected or did it still stop ok (albeit with no "feel" in the lever) I am interested to learn ?
PS; good article by the way

It was hard to judge where the locking point was.  The lever took a lot of pull force, and then all of a sudden, the front could lock, if you were not very careful.  I rode this way for 22k miles, so it wasn't horrible, though.

Hey Wookie, Just spent the afternoon on my front brake, the caliber is working perfect. I understand your thinking on 14 mm vs, 5/8, I'm there too! But everything is simple on the 74 single disc. I installed all new Japan manufactured OEM replacement parts, including hoses and distribution block. I loosened the two bolts holding the caliper, grabbed the brake and the lever moved almost full pull the tightened up, retorqued the bolts and it feed build back into the reservoir and tighten right up. I did this multiple times and it repeated. So matter what gap there is between the puck, the master and caliper does exactly what it's supposed to do. When I release the brake lever, wheel is free, so no dragging brakes. Actually it's a total of 1 inch pull for brake handle for a firm grip. Other than the distribution block, there nothing left in the system. I've worked on my own bikes for as long as I've been riding, 50 years now. I've had normal brake issues on bikes and cars but never ran into this. That's why I like forums! As much money as I've put into my Z1, a few more bucks isn't much to try to resolve the problem, especially brakes. I thought of the two disc conversion, buck that's a hefty price, but prefer to keep it stock as much as possible.
Thanks, Guys!

All good, I'm cheap and lazy so like to go for the "easy and free" options first 

Wookie, there are basically three pieces to the caliper.  The one closest to the spokes holds the fixed pad.  The one on the outside holds the piston.  The center piece holds the second pad that when acted upon by the piston will move towards the disc, squeezing it between the two pads.  We may be mixing terminology here.  I call the entire assembly the caliper.  The center piece is actually called a holder, presumably because it holds one of the pads.

The EX500 and a bunch of other Kawasaki models use a 14mm master.

IT's Fixed! I installed the new 14mm brake master and it's night and day, went from 1/2 inch pull to what felt like a wood block with the 5/8's, to perfect 2 to 3 inch pull with the normal brake feel.
I love forums , what did all of us old mechanics do before this? Thanks to all you guys!

Tpwood wrote:

IT's Fixed! I installed the new 14mm brake master and it's night and day, went from 1/2 inch pull to what felt like a wood block with the 5/8's, to perfect 2 to 3 inch pull with the normal brake feel.
I love forums , what did all of us old mechanics do before this? Thanks to all you guys!

we knew a guy, that knew a guy that understood hydraulic ratios, like Michael Morris

vintagebrake.com/mastercylinder.htm

slayer61 wrote:

Tpwood wrote:

IT's Fixed! I installed the new 14mm brake master and it's night and day, went from 1/2 inch pull to what felt like a wood block with the 5/8's, to perfect 2 to 3 inch pull with the normal brake feel.
I love forums , what did all of us old mechanics do before this? Thanks to all you guys!

we knew a guy, that knew a guy that understood hydraulic ratios, like Michael Morris

vintagebrake.com/mastercylinder.htm

I know a guy that posted that same link in this thread a couple of days ago.  Who knew?

It's amazing how great minds think alike & use the same resources!