KZ250 Top End Rebuild

Hi all,

My engine was rebuilt by the previous owner, but it wasn't a great job, as lots of oil leaks from the head. I've bough a new gasket set to replace the existing gaskets. There are a few o-rings and rubber gaskets that go between the head - I think that maybe some of these were reused or missed when the gaskets were done last.

The reason the previous owner replaced them is that the previous owner before him sold it as scrap, essentially. The engine made a huge amount of noise, and that turned out to be the camshaft being completely worn out. That's most likely caused by oil starvation to the head, which I have heard can be an issue with these engines. So I was going to make sure the oil lines are free - is there any magic way of doing this? I was going to try a combination of soaking parts, running drill bits though clogged up lines etc. Any advice here?

And finally, the oil pump. How often does one replace the oil pump on a motorbike? This one has done 64,000km, which is a fair bit for a 250, but whereas with cars people seem to do the oil pump at interval, I haven't heard anybody talking about oil pump replacement. Should I be looking at that too?

Top end lubricaton problems not usually oil lines clogged but oil strainer gauze or low oil level/defective pump.

IIRC the problem with the 250 is the plastic oil pump gear, other kawasaki bikes have had problems for this too. Google it and maybe try to find a NOS oil pump gear.

Oil pump removal on the other zeds is take the clutch basket off and drop the sump,The clutch centre nut is very tight and there are special tools for it. The oil pump bolts are threadlocked and staked so an decent impact driver may be useful here. The serice manuals have feeler guage wear specs for the oil pump, also you can check the oil pressure with a running engine.

I suppose it must be a matter of taking out the oil pump to inspect it then. The oil was very dirty when got it - I changed the oil and filter, and changed it again after 300km as it was already very dirty by that stage, so might be worth having a look at the strainer gauze. I think I might do the clutch at the same time anyway.