Fitting a 6 pot caliper to KZ440

Anybody tried putting a bigger caliper on a 440? These 6 pot Tokico's were used on a lot of different mid-90's bikes...ZRX, Hyabusa, ZX7, etc

Those particular calipers can be a real pain to bleed. A bunch of ZRX guys have tossed them in favor of four piston calipers. Better brake feel, too.

if you decide you need the six piston ones, be sure to buy the rebuild parts from Suzuki. They sell the seals in full kits for a fraction of the price that Kawasaki charges. Also, the Hyabusa uses aluminum pistons which are much lighter and less prone to corrosion than the anodized steel ones from Kawasaki.

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Those particular calipers can be a real pain to bleed. A bunch of ZRX guys have tossed them in favor of four piston calipers. Better brake feel, too.

if you decide you need the six piston ones, be sure to buy the rebuild parts from Suzuki. They sell the seals in full kits for a fraction of the price that Kawasaki charges. Also, the Hyabusa uses aluminum pistons which are much lighter and less prone to corrosion than the anodized steel ones from Kawasaki.

I had a ZRX back in the day so I know about the bleeding adventure & the rebuild kits from Suzuki.  At least if this can be made to work on the 440 it's just one caliper    I'm hoping someone using the caliper can measure the distance between the back of the mount bolt to the back of the caliper.  There's quite a bit of space between the stock caliper & the wheel spoke.  The Tokico is wider because of the opposed pistons but it looks promising...

Suppose the rotor diameters aren't that different, so it would likely physically work, but I am concerned that it might be too much for our skinny tires.

Suppose you could play with different master cylinders to get it under control, but I've locked the stock brakes on my 750 and my old 305.

I was looking into using 2-pot calipers from an EX500 at some point, those may be cheaper to buy/rebuild, plus the bike they come from has more similarly sized rotors. Either way you'll need to make a mounting plate/adaptor.

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Suppose the rotor diameters aren't that different, so it would likely physically work, but I am concerned that it might be too much for our skinny tires.
 

And for the comparatively weak frames.

The 440s were not designed to handle that much braking force.

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Suppose the rotor diameters aren't that different, so it would likely physically work, but I am concerned that it might be too much for our skinny tires.

Suppose you could play with different master cylinders to get it under control, but I've locked the stock brakes on my 750 and my old 305.

I was looking into using 2-pot calipers from an EX500 at some point, those may be cheaper to buy/rebuild, plus the bike they come from has more similarly sized rotors. Either way you'll need to make a mounting plate/adaptor.

Yeah, the adaptor is expected but I've done that on several bikes.  Technically speaking, the stock caliper isn't sliding pin but it's similarly designed & trying to stuff a traditional opposed piston caliper in where sliding pin calipers live likely nets clearance issues.  I could always use another sliding pin caliper with twin pistons to get more surface area of the pads to increase braking power.  But I prefer to get the most out these things so if I can fit that 6 pot caliper, I will.  There is about 1 3/4" between the back of the mounting boss & the wheel spoke, 1 1/4" from backside of the rotor & spoke.  Ebay is full of 6 pot calipers for dirt cheap...might just pick one up & if the measurements don't work out it's not that much of a loss.

I don't think the wheel is the limiting factor but the forks could be.  I did something similar to my sons CB360.  The stock front brake was atrocious...had more braking from the rear drum than that front.  The stock brake carrier was riveted to the disc & it was dumb luck that a spare stock front brake off a 97 Vmax lined up exactly to the rivets on the Honda carrier.  I ground off the rivets, tapped the carrier for 8mm bolts & put a 298mm rotor on a wheel that came with a 260mm.  Had to make an adaptor to fit a sliding pin caliper from a Honda Fury.  The stopping action from that combination was violent.  I begin noticing the forks flexing when pressing it hard.  

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.  There is about 1 3/4" between the back of the mounting boss & the wheel spoke, 1 1/4" from backside of the rotor & spoke. 

I don't have a measurement for you, but I tried to test fit a ZRX 6-pot on a '78 kz1000 with a cast wheel. The caliper body hit the spokes.
I suspect that you would need to make a spacer to move the disk away from the wheel. There are many examples of these spacers used by other folks on this site when swapping calipers.

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.  There is about 1 3/4" between the back of the mounting boss & the wheel spoke, 1 1/4" from backside of the rotor & spoke. 

I don't have a measurement for you, but I tried to test fit a ZRX 6-pot on a '78 kz1000 with a cast wheel. The caliper body hit the spokes.
I suspect that you would need to make a spacer to move the disk away from the wheel. There are many examples of these spacers used by other folks on this site when swapping calipers.

well shoot...not surprised though.  There isn't much space to move the rotor either...rivets only leave maybe 5mm or so before they'd contact the caliper.  No worries though.  Think I read elsewhere that some of the early KZ1000's use the 4 bolt rotor that fit on the 440 wheel.  If I can't get more braking from a caliper, a bigger rotor will work too.

Read somewhere the 4 bolt brake rotor for 79-81 KZ1000 would fit the 440...it doesn't.  Center hole is too small & the bolt spacing is just a couple of mm off.  It's the 295mm front rotor though & I'm wondering if they weren't talking about the rear rotor.  I think the rear rotor is 290mm & I'm not sure I want to go that route.  It's not that much bigger than the 275mm that's on the bike & the braking isn't terrible with the 1/2 inch master & braided brake line.  I've got another caliper I'm going to try out.  Maybe the wider sweep on the pads & the master cylinder/brake line, I'll be content with it.  It's too bad...she was a pretty rotor 

The bigger brake rotor turned out to be a lost cause but a 2 piston caliper has wider pads/more surface area & gives a noticeable effect on braking.  Picked up a caliper for a 2016 Yamaha Bolt, fabricated an adaptor from 3/8" 6061 aluminum plate.  Wish the master cylinder was a 12mm instead of 1/2" but it's better than the stock ratio so I can live with it.

Don´t play stupid games with brakes. Your brake pad to disk surface ratio is a no go !!!