TOPIC:

Finished my KZ650B. Stock single disc. I am wondering how to do dual discs on the front while retaining the stock wire wheel. I can source a second caliper but how does one mount the disc? Anyone? TIA.

You have to remove the chrome wheel hub cap that covers the 2nd disk bolt holes.

 
 
 
 
 
 
 
 

A pic will help identify the wheel you have. 
Steve

Simple job. 
Undo the two screws that hold on the chrome hub cover on the rh side. 
Bolt on another disc, ( 4 bolts, lock tabs and disc) 
Mount a r/h caliper with two bolts. The calipers are handed so you'll need a rh one making sure it has the bleed nipple central if front of leg mounted caliper. (2 bolts and rh caliper). 
Add additional lower hose, and twin outlet Splitter. (lower hose and twin outlet Splitter) 
You'll also need a 5/8th dia master cylinder as opposed to the 1/2in dia single disc version you already have.( 5/8th master). 
Items in brackets is your shopping list plus (fluid and pads) of course.
To make it a really effective upgrade swop all hoses for new braided versions. 

Scirocco, thank you. I was just looking for the axle torque last weekend at the Zukey Lake outing. It’s not noted in any of the Z1 manuals I have. 

 

I copied this down from a post on the now no longer working kz650.info site. In  looking at the file it appears I did so in 2012 so take it with that knowledge. 

Ok, let me 1st give credit to Steell from KZr & the twins forum, he pointed me in the right direction;

Using www.kawasaki.com 's microfiche;

If you have the forks from these models (fork lower section)
KZ1000-A1 (KZ1000) (1977)
KZ650-B1 (1977)
KZ650-B2 (1978)
KZ650-B2A (1978)
KZ650-B3 (1979)
KZ750-B1 (1976)
KZ750-B2 (1977)
KZ750-B3 (1978)
KZ750-B4 (1979)
KZ900-A4 (1976)
KZ900-A5 (1977)
KZ900-B1 (LTD) (1976)

And the hub from these bikes
H1-D (1973)
H1-E (1974)
H1-F (1975)
KH400-A3 (1976)
KH400-A4 (1977)
KH400-A5 (1978)
KH500-A8 (1976)
KZ1000-A1 (KZ1000) (1977)
KZ1000-A2 (KZ1000) (1978)
KZ1000-A2A (KZ1000) (1978)
KZ650-B1 (1977)
KZ650-B2 (1978)
KZ650-B2A (1978)
KZ650-B3 (1979)
KZ750-B1 (1976)
KZ750-B2 (1977)
KZ750-B3 (1978)
KZ750-B4 (1979)
KZ900-A4 (1976)
KZ900-A5 (1977)

The 12 inch Brake Disc's / Rotors off all these models will bolt straight onto the hub
KZ1000-A3 (KZ1000) (1979)
KZ1000-A3A (KZ1000) (1979)
KZ1000-A4 (KZ1000) (1980)
KZ1000-B3 (KZ1000 LTD) (1979)
KZ1000-B4 (LTD) (1980)
KZ1000-C2 (Police 1000) (1979)
KZ1000-C3 (Police 1000) (1980)
KZ1000-C4 (Police 1000) (1981)
KZ1000-D3 (Z1R) (1980)
KZ1000-G1 (Classic) (1980)
KZ650-E1 (LTD) (1980)
KZ650-F1 (1980)
KZ750-G1 (LTD II) (1980)

Then you use Calipers from the 83 - 85 GPz 750 (these may be on other bikes but i dont know which ones, no diagram on the fiche)

You will also need a different master cylinder so it can push enough fluid to cope with 2 discs. One that is used with a twin disc setup & has a mirror mount can be bought cheaply on ebay, perhaps one off a GPz 750/1100 ?

Voila............twin front discs on a B model 650, and really good brakes at that!

If im correct the disc / rotor thickness on the B models is 7mm ish (they're a heavy old bugger), the replacement discs are 4.5mm ish & are much lighter so you get WAY better brakes with about the same unsprung weight.

IF your original caliper is in front of the forks you can reverse the forks like this, imagine jacking the front end up by the engine, loosen the upper & lower fork clamp bolts & remove the forks & wheel as a complete unit, turn the whole thing through 180 degrees & slide it back in. Obviously you need to disconnect the speedo & master cylinder or they will tangle. Your speedo drive will be on the opposite side now AND you will have to do away with the stay for the front mudguard as it will be at the front of the fork now (yes you must remove the mudguard & turn it the opposite way too)

If your bike is the single disc model (as i think all B models are) then remove the cone shaped cap on your front hub on the opposite side of your original disc & the facility is there to bolt another disc on, this may be obvious to some people but not others  

You can see my 1977 Z/KZ 750 B2 Twin is in both fork & hub listings, i've done it thanks to Steell & i know it works now too!

If there is any confusion from non European members then substitute the word 'Disc' for 'Rotor' & you should be fine!