1978 KZ650D1 Front brake master cylinder

I've been unable to find a rebuild kit for this master cylinder. I've found them for many others but not this one. I'm looking for a source or advice about rebuilding this component.

Any help is gratefully appreciated!

in some cases you can take it apart, clean it up and reuse the old parts. is it leaking??

If not already done, would try ordering any needed master cylinder parts through a Kaw dealer, because kawasaki.com shows the following oem parts as being still active (available):

Piston 43020-1023

Dust cover 49016-1010

Reservoir diaphragm 43028-1002

Sometimes, a master cylinder may be renovated by a thorough cleaning, dressing any pits inside the bore, and maybe a new piston.

Good Luck!

I ordered a rebuild kit for my D1 from Z1 Enterprises. It's only for the piston, not sure if they have the resevoir parts or not. It has worked perfectly and was very easy to install.

www.z1enterprises.com/SearchResult.aspx?...e&KeyWords=KL32-8052

HerrDeacon wrote:

I ordered a rebuild kit for my D1 from Z1 Enterprises. It's only for the piston, not sure if they have the resevoir parts or not. It has worked perfectly and was very easy to install.

www.z1enterprises.com/SearchResult.aspx?...e&KeyWords=KL32-8052

That's some real good information, and the part number is consistent, but I missed seeing it when searching under Z1E's 1978 KZ650 parts listing, where it's omitted for some reason.

Shown under the quoted link is the following:

Master cylinder Rebuild Kit - double disk version (5/8")
KL32-8052

OEM: 43020-1023 49016-1010 43022-1001---

Contains all the parts to rebuild one (1) 5/8" master cylinder. This mastercylinder is typically used only for double disk setups. Given the age of these bikes, it is worth checking that the master cylinder is correct for the bike - most of these master cylinders will have 5/8" cast into the underneath of the master cylinder.

Fits KZ550-D1 KZ750E KZ750H KZ1000-A3 KZ1000-A4 KZ1000-B2 KZ1000-B3 KZ1000-B4 KZ1000C KZ1000E KZ1000G KZ1000-J1 KZ1000-J2 KZ1000K KZ1000M KZ1000-P1 thru P10 KZ1100-A1 KZ1100-A2 KZ1100-B1 KZ1300

$32.37



You betcha I would concur with Z1E as first choice inquiry!

Good Luck!

Yeah, I couldn't find it under the '78 650 either. I think I searched for it and double checked with everyone on this site before I bought it.

Mark, is yours the trapezoid shaped MC with dual discs?

Yeah, it's leaking. I think I'll need at least new o-rings.

Yes, with the 5/8" stamped on the underside. I saw the part you mentioned @ Z1 and wondered if it would work.

And the reservoir appears to be OK. It's leaking out of the brake lever end. I've have really good experiences with Z1. Thanks!

markc3wa wrote:

And the reservoir appears to be OK. It's leaking out of the brake lever end. I've have really good experiences with Z1. Thanks!

That's where mine was leaking. Used to flick back while riding and it ruined my paint on the tank

The new piston kit fixed it perfectly.

I have the same problem, in the fact that my reservoir is leaking too. It leaks from the top, because the original gasket between the reservoir and the "lid" is now gone. Do you know where I might find just the gasket. I talked to Z1 and they said that it is no longer carried, by anybody. I need this to pass my inspection that is a month over due. Thanks so much for your help guys!
Kcam1999

kcam1999 wrote:

I have the same problem, in the fact that my reservoir is leaking too. It leaks from the top, because the original gasket between the reservoir and the "lid" is now gone. Do you know where I might find just the gasket. I talked to Z1 and they said that it is no longer carried, by anybody. I need this to pass my inspection that is a month over due. Thanks so much for your help guys!
Kcam1999

There really isn't a gasket there since air must be allowed in to compensate for changes in the fluid level. How it's done is that accordian looking thing inside the master cylinder is vented to the outside air in the center only, the outside of it is sealed. It's a diaphram, so when the fluid goes down the accordian pulls down with it since air is allowed in the center. So in other words the accordian diaphram is the gasket and part number is 43028-1002 available through any kawasaki dealer.