KZ400 Oil Leak

Hello All, with my '75 KZ400D I've got the famed oil leak around the head. I've had it ever since I bought the bike but it slowly seems to be getting worse. Too bad it wasn't fixed under warranty back when it was new. Of course it leaves a its mark on the ground whereever I park it and since I live on a gravel road the dust sticks to it and makes it look even worse.

The question is how hard is it to remove the head and install new o-rings (that is generally what is causing this, right??) Is there any gotcha's that I need to worry about or am I better off having a shop take care of it, of course its not like I can afford to have them do it, but anyhow...

I had read somewhere that Kawasaki had replaced the original o-ring with some type of o-ring with a aluminum ring inside to help seal the oil passage. Is this true and if so, are they available anymore or should I just buy an oil seal kit (looks like its got several o-rings in it) from eBay or somewhere.
Thanks, Tony

Post edited by: tonykz1, at: 2005/10/19 09:01

Post edited by: tonykz1, at: 2005/10/19 09:02

Are you saying you're leaking from around here?:





If so, you need a new one of these so-called O-rings:




...believe it or not, I've seen them on eBay... I fact, I've bought one from eBay...

Odd Ivar's KZ400 website is usually a great source of info for these type issues. If his site doesn't have the info you need, I would contact him directly. I would also consider reassembling with a new o-ring and using a sealer such as Hondabond HT or similar.

Well, I don't know if it's coming from around there (between the head cover or adjuster covers and the head or if its coming out between the head and cylinder. I guess I need to clean it up real good and check again. Yes, I've been to Ibsen's site and I go back there quite often, very informative web site.
Tony

Post edited by: tonykz1, at: 2005/10/19 09:38

I’ve done that job a lot of times; 8 at least, the first time in 1979 when my bike was only a baby of 2.
The kz 400 had an oil leak problem from the factory, and as you said, it was repaired under warranty for original owners.
The owner of the shop I used to go to [north Reading, Mass] told me the flat rate time was 5 hours for the job, and none of his mechanics could get under that. I do it in 4 or 5 hours now, but it took forever the first time.
Is it hard? I would say yes, but it’s a relative thing. You definitely should have a shop manual; there are several “gotchas� in there; mainly getting the cam back in the right position. You don’t really need any of those special tools though, except a torque wrench. You can probably rent one.
You can buy a complete head gasket set with all the O rings [a couple of them are ovals] and a head gasket with adhesive on it already. You definitely need a new head gasket each time. The original leak repair kit even had new engine studs, but I don’t think you really need them.
You should get new O rings for the valve adjuster caps [might or might not be in the head set]. The caps on the ’75 model had a wide and weak shoulder, so be gentle with them. If any are broken, replace them with [used is fine] ‘77 or later ones, which are built a bit tougher.
The important ones are the oil galley rings, which are the oval ones. Strangely, the cylinder oil passages don’t line up with the head oil passages, so the oil has to squirt sideways slightly [hence the oval O ring] before resuming its upward path.
You can get any O rings not included in the head set [the adjuster cap O rings and probably the cam chain adjuster O ring] from an auto parts store if you know the sizes. Just take the cleaned cap with you.
Regarding the valve cover O ring someone sent in a picture of; I haven’t had one of those in my bike for 15 years now. I use permatex blue gasket silicone. Works fine.
Mostly I’ve had to take the head off to clean the carbon out of the combustion chambers, since here in India the gasoline is usually cut with [cheaper] kerosene. Once you put new seals in, it won’t leak for years.
Have fun, Mark Holden