Oil Leak

Hi all. I have a 79 650. I bought it as a project and have gotten it started up. There is an oil leak in front of the engine. I hosed it done with degreaser and was hoping it was the tach drive but fired it up today and let it run for 10 minutes and I could see oil on the defuser / keeper on the #3 cylinder. I am not seeing any smoke coming from the exhaust. Could it be the gasket is bad or is it more than that? Thanks guys!

i'm not sure what a defuser is exactly, but the fact is KZ650 used a lot of rubber orings. They are everywhere, there are probably 100 orings on a KZ650 vs maybe 20 on a KZ1000. Numbers are just a wild guess, but for some reason Kawasaki chose to not copy a Z1 design into the KZ650 line. They chose rubber and lots of it and all will leak after exposure to time and heat. Gaskets can leak, but orings are the low point in leaks on a KZ650. Look at diagrams to where they all are. Big pain in the rear on a KZ650. Always has been.

Kawabob wrote: Hi all. I have a 79 650. I bought it as a project and have gotten it started up. There is an oil leak in front of the engine. I hosed it done with degreaser and was hoping it was the tach drive but fired it up today and let it run for 10 minutes and I could see oil on the defuser / keeper on the #3 cylinder. I am not seeing any smoke coming from the exhaust. Could it be the gasket is bad or is it more than that? Thanks guys!

What is a defuser? Got pictures? ed

Sorry I was not very clear on my post guys. The oil is leaking onto the #3 diffuser / keeper. It is the part that hold the header onto the engine. There are two split keepers that push the flange of the header into the exhaust port and those are held in by what I call a diffuser. The gaskets used to be made of copper I think. Could these have finally gotten too flat to seal or could this be a bad valve / valve guide? As in the previous post I am not seeing any smoke from the exhaust.

My first attempt at an attachment was too big lets try this

I know you checked, but I'm still thinking it's the tach seal. I say that because for oil to be all over the exhaust pipe holder (diffuser) it looks like it would be coming from above. Also, since the exhaust isn't smoking it is doubtful that that oil is coming from the cylinder through the exhaust port. I would clean that whole area squeaky clean and then run it to see where oil is coming from. Maybe dust it with talcum powder to help show the source of the leak. Ed

OK Ed, appreciate the reply and it makes sense with the oil from the tach drive dropping onto the header / diffuser. I will hose her down again with degreaser and watch her like a hawk! Talcum powder is an interesting idea as well.

Bob

Id agree on the tach drive being the problem, probably best to take the cylinder cover off remove tach drive check if there is a o ring there , also check the tacho cable there could be a few parts that seal it correctly missing.

Check against the parts diagrams at Kawasaki.com


shouldn't be too big a deal to sort it out!!

Thanks chirpy, when you say "take the cylinder cover off" what are you referring to? The tach drive as it attaches to the cylinder?? Thanks

Bob

I had a hard time a while back getting the tach seal leak to go away. I bought new o-rings, etc and it persisted. Ended up finally getting it sealed. Try the Permatex Motoseal product. Works well for me.

OK, I cleaned the area well and started it up, after 5 minutes or so I could see the oil on the holder for the header and the tach drive was clean....so next step??? Should I do a compression test....change the header gasket? Would the oil more likely be coming from a valve guide or from bad rings? I guess a compression test may narrow it down??

Ok, here’s some theory (like most theories - not necessarily true.)

If that much oil was the result of bad rings I would expect oil to be in the combustion chamber during combustion. This should make the engine run poorly and smoke rather badly as the oil burns. Your bike isn’t smoking, so that’s a good sign.

If the oil was the result of a bad exhaust valve seal the oil may be coming out past the exhaust valve stem when the valve is open during the exhaust stroke. If that is the case, since there is no combustion at that point in time there may not be enough heat to burn the oil to make it smoke. So the oil may simply migrate around the header area until it is pushed out by exhaust pressure.

I would expect that your compression test will be helpful in identifying if the oil is the result of bad rings, so that’s a good place to start. Ed