Fluid Leaking onto front brake lever - newbie

Just learning to work on my KZ650. Does anyone know why there might be fluid leaking out onto my front brake lever. It doesn't happen all the time, and it's only a small amount. It could be brake fluid, but seems to be darker. Any help would be great.

Sounds like you have a bad rear seal (where handle pushes in) in your MC. Fluid is "darker" because it's probably dirty. Time for a rebuild. :ohmy:

Bluemeanie wrote:

Sounds like you have a bad rear seal (where handle pushes in) in your MC. Fluid is "darker" because it's probably dirty. Time for a rebuild. :ohmy:

Thanks for the quick response, are there rebuild kits for this, or do I have to take it apart and look at which components to replace??

They sell kits. What year and model 650 do you have?

To help locate source of leak, cover tank with towel, clean the master cylinder and brake lever area by spraying it with common rubbing alcohol (use a hand water bottle sprayer, which often fits onto the plastic alcohol bottle). Blow with compressed air if available, or just dry it off with the towel.

With everything clean and dry, it's much easier to locate the leak.

As Bluemeanie suggested, the leak is likely from the rear seal (being a rubber "cup" often built in as part of the internal piston assembly). Such leak would ooze out onto the lever where the lever pushes on the master cylinder.

Other possible leak sources could be at the banjo bolt fitting where the brake line attaches to the master cylinder, or the rubber gasket which supposedly seals the lid or cap on the master cylinder.

Before proceeding, it would be helpful to have a factory service manual for reference, or to at least study the master cylinder parts diagram on www.kawasaki.com .

Good Luck!

It's a 1978 kz650 B. I would like to find a kit so I can have the parts there while I figure out where the leak is coming from. Where can I get a kit from??? Thanks for the help, I will probably be on here a lot. It seems like there are always little things that pop up, but the bike runs so great, it's totally worth the time.

contact z1 first, you can find them in the link section, they are good people

Does your bike have a trapezoid shaped master cylinder? This master was used on the 650 and some single disc 1000's in 78. I was looking at Redline Cycles and on their brake pages you can find the kits. I would take the master apart first, and then compare the parts you have to those pictures. They don't mention that they will fit the 650, but I'm sure these will fit. You can always call and ask what the Kawasaki part number is and check on the BuyKawasaki.com website to see if they are the part that will fit your bike.
Good Luck

The "kit" is really not all that complex. There should be one part. The piston is the only part.

OKC_Kent wrote:

Does your bike have a trapezoid shaped master cylinder? This master was used on the 650 and some single disc 1000's in 78. I was looking at Redline Cycles and on their brake pages you can find the kits. I would take the master apart first, and then compare the parts you have to those pictures. They don't mention that they will fit the 650, but I'm sure these will fit. You can always call and ask what the Kawasaki part number is and check on the BuyKawasaki.com website to see if they are the part that will fit your bike.
Good Luck

It has a round master cylinder, and it has dual disk brakes. Are these parts possibly off of a 77?? My manual shows the round cylinder on the 77. I am getting into it tomorrow when I have time. This is a great forum, you guys have been amazingly helpful. Thanks!!!

Pulled off the master cylinder, the rear cup had a tear in it. I want to inspect the rest of the parts for damage but how do I get them out?? The manual is very vague, and I don't want to damage any of the other components.

When you say "rear cup" that means the rubber cups on the cylinder piston, yes? If you have the piston out I don't think there is much more to take apart. Or do you mean the rubber cover, number #17 ?