1975 KZ400D - restore project

Z1s leak at the stator grommet. Many threads on it. Oil will wick through where the wires are, not just on the perimeter of the grommet. I cleaned and cleaned and cleaned again with brake clean. Then used Permatex form a gasket and let it setup for a few days before reinstalling. That was years ago, still dry.

I feel like there is some underlying issue besides a failed gasket...on the 75 400d2, is there a way pressure builds up on the left case?

Yes. there is a way for oil and pressure to build up in the left cover (alternator cover).
The oil comes in through the crankshaft. The crankshaft has a small hole on the starter-clutch-sprocket bearing surface, then is supposed to seep back into the crankcase along the outside of the crank, but inside the starter-clutch-sprocket bearing. There are two seals involved. One seal is in the starter-clutch-sprocket between the starter clutch and the crankshaft. The other seal involved is in the crankcase between the crankcase and the starter-clutch-sprocket. If either one leaks you will get oil in the alternator cover. I think the starter-clutch-sprocket seal may be more important for keeping out oil because that one has to hold oil pressure.

I could have sworn I saw a path for oil to get back into the crankcase on some 400/440 motor, but the 1976 D3 I am currently working on absolutely does not have a return opening. So oil builds up in the alternator cover and it leaks. I'm not sure if actual pressure builds up. If the actual starter-motor is sealed and sealed to the crankcase, then I guess pressure would build up too.

I took photos of the crankshaft oil passage to the starter-clutch:
www.kzrider.com/forum/11-projects/611489...400-s?start=0#811430

Oh, this isnt good, so what youre saying is I perhaps have a bad seal on behind the stator? Orrrr can that seal be replaced without messing with the bottom cases? Man that would be tits!

Thanks for the reply...

Jack_Mills wrote: Oh, this isnt good, so what youre saying is I perhaps have a bad o ring on the bottom end

Thanks for the reply...

No. I'm saying maybe your leak is the seal on the starter-clutch-sprocket. That's easy to get to, but I'm not sure how available they are.

GREAT! CMS has all the seals if no one else has them on ebay or what not. Thanks for the info..Im going to tear into this job a bit later today.

Please let us know how it goes. I have to do the same thing on our Kz400.

If you get a chance, please post the part numbers you used so I can be sure to get the right ones.

Also, can the crankcase seal be replaced without splitting the case open?

I attached a diagram of how I understand it.
During normal running, the sprocket is not moving while the crankshaft is turning inside of it, so it needs oil.

I only bought the outer oil seal (I dont see the inner one on the microfiche)
Oil seal: 92050-066
I also bought a new thrust washer: 92026-100

I have a feeling that the inner oil seal (if there is one like youve shown) wouldnt be accessible unless taking the bottom end apart and that sucks! haha

Ok, thanks for the part numbers.

I have a 76 400D3 engine apart...Its in a crate at the moment, but perhaps I can take a look at it in the up and coming days. It has to come all the way apart so I can send the parts for vaper blasting...so many projects, never enough time.

www.CMSNL.com (and many other websites) have copies of the microfiche to cross reference part numbers. Here is a direct link to the 74-75 D2 and at the bottom of the same page they have some of the 76D3 parts lists.

www.cmsnl.com/kawasaki-kz400d-1975-canada_model15458/partslist/

For some reason, I can't find that crankcase oil seal on any fiche, not even for the 2nd gen Kz400 motor cases. Sometimes there is a note next to an oil seal which says whether the cases have to be split to replace a seal. I was actually looking for that note, but I can't even find the actual seal on the fiches.

Maybe someone with more coffee on hand can find it.