KZ400 cam bearing wierdness

I had to pull the valve cover on my KZ400A2 deluxe to have a broken extractor removed from the rocker adjustment cover. I noticed that the cam journals appear to be larger that the cam bearing surface, the cams do not fill the cast journal in the cover, but appear to fit in the head. I thought the cam mating surfaces were machined together at once? It appears that the head cover was never tooled except where the cam touches. That stuff on the bearing surface is RTV, the PO was in here and went nuts with the stuff. I have no clue how it has not worn off. What should i be looking for here? Perhaps a different valve cover was fitted at some point, and because they were not machined together it did this? Should i start looking for a new head/cover to fit?

DoctoRot wrote: ......I noticed that the cam journals appear to be larger that the cam bearing surface, the cams do not fill the cast journal in the cover, but appear to fit in the head. ......

Take a look at the pics in the link below. If you click on the large pic it will come up even larger. It appears that the journals are the same as yours in that they are only partially machined. Ed

www.c4powersports.com/servlet/the-2758/K...-KZ400-KZ-400/Detail

I don't have much experience with the early 400.
By looking at the first pic of your rocker box
the head is cast that way. There is a lot of 1194 in
there that isn't needed. Also the outer bearing journal
looks like it is mushroomed out. I would check cam
t o journal clearances.

The heads are line bored as a set. You might be better off with a good used head set or have yours built up and rebored to fit the cam.
Steve

650ed wrote:

DoctoRot wrote: ......I noticed that the cam journals appear to be larger that the cam bearing surface, the cams do not fill the cast journal in the cover, but appear to fit in the head. ......

Take a look at the pics in the link below. If you click on the large pic it will come up even larger. It appears that the journals are the same as yours in that they are only partially machined. Ed

www.c4powersports.com/servlet/the-2758/K...-KZ400-KZ-400/Detail

Looked at a bunch on ebay too, they all appear to have the partially machined journals as well. Seems like a strange decision on Kawasaki's part. All the other KZ heads I have seen have had a good fit around the cam. I was alarmed because it looked so out of place, but it appears to be this way from the factory. I will check the cam to journal clearances to be sure.

My old 73 350 Honda had eccentric adjusters like the one you have. The cam bearings were part on the adjuster blocks that bolted on each side. It didn't have a oil filter. It had a drum that would spin with the crank and the particles would collect against the vanes inside. Horrible design. If a oil problem occurred, the cam blocks would be ruined I liked the fact I could adjust the rockers from the out side but I dropped a valve because I adjusted it too tight. Yours appears to be a oiling problem. I can see some of the sealant you were talking about. The bearing surface on the head it shot. It has to be fixed or replaced.
Steve

After cleaning the bearing surfaces, they don't appear to be in too bad of shape. I had a chance to plastigauge the journals tonight. They all seem to be in order with the largest journal being .075mm. The normal range is .043-.101mm, with a service limit of .19mm; that seems pretty big to me. My only concern is there appears to be a small score in one of the journals. I can't seem to get a photo of it its so small, but it is there. It wont snag my fingernail or anything, so Im thinking I should let it be. If I end up having trouble with the engine running this will be something I will return to.