DOHC's blue Z1R Refresh

It IS beautiful though!

I like the originality, your a lucky man. Great job. Go enjoy it. 

Bikes looking Great !!!!!!!!!!!!!!!!!!

According to Partzilla, the 1980 caliper was used on a bunch of different models.

www.partzilla.com/product/kawasaki/43041...4eb87f68cfefa0492edc

I don't have experience with Z1R brakes but I can say that those round puck pad calipers are pretty lame.  Wooden is a good description, and the pads often squeak too.  Some later year calipers would be a good choice for a daily driver bike.  I'd also consider ditching the cable operated master.  You can always slam on the originals for shows or if you go to sell the bike some day.

TexasKZ post=853815According to Partzilla, the 1980 caliper was used on a bunch of different models.

www.partzilla.com/product/kawasaki/43041...4eb87f68cfefa0492edc

Yeah, it looks like the left side caliper was used from 79 (maybe some in 78) until 1983 on the KZ440.  But the right side caliper is less common.

www.partzilla.com/product/kawasaki/43041-1025

I really hate the new diagrams, where they mix up all the years.  I really miss the old Kawasaki parts database.  It was really great.  

Anyway, looking over the diagrams it looks like the 77-78 dual-disk bikes (1000B, 1000C, 1000D, 650C, 650D) used the small pistons, while the 79-80 dual-disk bikes used the larger pistons, with maybe some transition for some models between 78 and 79.  The single-disk bikes used the larger piston from the start, so I could probably use a left side from a wider range of years.

The nice thing about switching to the large piston calipers is that they look exactly the same as small piston calipers.  The hard part about finding a good set on ebay is that they look exactly the same as small piston calipers. 

Anyone know of a different caliper that is a direct bolt on?  Any chance that the later 81+ calipers from the J or GPZ or 750 are direct fit?

The trick with switching to a different master to get rid of the cable is that there is very little clearance between the handlebar and the fairing.  Maybe I could get away with one of those fancy radial master cylinders with remote reservoir, since it would stick straight out, but a regular old KZ master won't fit.

 

I've been thinking more about resleeving the master.  I have a spare that is in rough shape, and there is a place near my house that rebuilds all kinds of brake parts.  My buddy is very confident they could do it.  I already figured out that the Z1R master uses the same rebuild kit as the standard trapezoidal KZ1000 master.  And it looks like they made that style in both 5/8" and 14mm, so maybe the rebuild kit for the 14mm version would fit the Z1R master?  

www.z1enterprises.com/m-c-kit-double-dis...rsion-5-8quot-2.html
www.z1enterprises.com/m-c-piston-kz650-7...kz400-kz1000-a2.html

I think I'm going to go talk to those folks and see if they can really sleeve it, and then see if the parts might fit.

Looking great!

If you can get a good pair of the large piston calipers and get your master sleeved down to 14mm, I bet you would have the best setup possible without spending big money and making a bunch of modifications. Like any mod, it can turn into a black hole pretty quickly. A Brembo radial master with a pair of Brembo radial calipers and some custom hydraulic lines with some lightweight rotors would be fabulous. Might cost less than a new car…….

wrote:

If you can get a good pair of the large piston calipers and get your master sleeved down to 14mm, I bet you would have the best setup possible without spending big money and making a bunch of modifications. Like any mod, it can turn into a black hole pretty quickly. A Brembo radial master with a pair of Brembo radial calipers and some custom hydraulic lines with some lightweight rotors would be fabulous. Might cost less than a new car…….

But based on that article I linked the target ratio would be 12:1 to 14:1, with that author's preference of around 13.5 : 1 (I think).

It seems like I can get a better ratio by changing one or the other (master or calipers).  But if that article is correct, It seem like doing both would be a bit too far. 

Here are the numbers:
5/8 master, 38mm pistons : 11.54 : 1
5/8 master, 42.8mm pistons:  14.54: 1
14mm master, 38mm pistons: 14.84 : 1
14mm master, 42.8mm pistons: 18.70 : 1

But wait!  I have been thinking about an entirely different way to skin this cat.  I've been thinking about making a lever for the master cylinder, where the cable mounting point is moved out to increase the leverage. It may be unreasonably expensive to have one machined.  Also, the cable might not appreciate coming out of the housing at an angle.  And other possible issues.  But I figured I'd look into it.  This could allow me to try different ratios quickly.   

A cable accutated MC gives you not the right feedback feeling to the break pressure point. Too much strain on any parts and joint points in the entire system.
A longer MC lever need more pull way on the cable and end up with more strain in the entire system.
A 2" wider steering bar gives you the option to install a real MC and you will get a better control/feedback to your front break. Just my 2 cents...

That article seems focused on single disc systems. My ZRX came with a pair of six piston calipers with a total of 3195 sqmm, and a 5/8 master. Several guys on the ZRX discussion board have changed to 14mm masters and reported significant improvement. The better upgrade uses a 14mm master with a pair of Nissin four piston calipers with 3230 sqmm. Perhaps dual disc setups require a completely different ratio.

If I have done the math correctly, the stock setup would be about 16.9:1 and the stock calipers with a 14mm master would be 20.09:1.

I do run a double six piston Tokico with a Z1 single disk (1/2?) MC with no problems. The front break bites like hell with a perfect feedback.