'81 KZ1000 cylinder O-rings

Thanks, it's been a long slow process, but it's coming up towards the end and I'll finally be able to ride it.

daveo wrote: Stock Kawasaki gasket setup would be two head gaskets, four 18.5mm special o-rings, and one center o-ring.

Good luck, and take your time as you work through the critical assembly steps.

Oh, just remembered...Jeff at Z1E advised me to install the o-rings dry, with no sealer or anything applied. That was back in 2015, and there has been absolutely no seepage of oil to date. Having APE cylinder stud/nuts really helps with that.
I regularly operate this engine from 5K to red line, and that baby has remained sealed tight as a drum.

Humm...it'seems always been a rule of thumb to lubricate o-rings with the fluid they are going to seal. Makes a smoother fit when torqued, and prevents pinching on other applications.

In this situation the special-shaped corner o-rings are compressed between two flat surfaces coming together, which don't slide past one another to arrive at their final position, so they would not benefit from lubricating. I may be all wet with that thought...but maybe not...:blink:

My question for Jeff was more about applying a thin film of silicone sealer on each o-ring before placement in the cylinder block recess, thinking that could potentially improve the seal by bonding it in-place...nah.

daveo wrote: In this situation the special-shaped corner o-rings are compressed between two flat surfaces coming together, which don't slide past one another to arrive at their final position, so they would not benefit from lubricating. I may be all wet with that thought...but maybe not...:blink:

My question for Jeff was more about applying a thin film of silicone sealer on each o-ring before placement in the cylinder block recess, thinking that could potentially improve the seal by bonding it in-place...nah.

I researched this a while back, and you would be surprised of the advantages of lubricating o-rings. Even when between two flat surfaces, there is a small amount of friction that takes place when the o-ring gets compressed. The lube also has some preservative properties. Google it. There are even a few companies that specialize in o-ring lubricants.

Some people believe that a silicone sealant on rubber is against the rules. I work for Honda and in several instances (tight corner on a rubber pan gasket for example) they recommend sealant to insure a good seal. Just like Kawasaki recommends sealant around cam plugs on install. And you always want a dab of sealant where a gasket covers a metal to metal seam, like an engine cover against the case halves.

Oh, as far as sealant on the outer head o-rings, I just apply engine oil. When you apply sealant and compress the o-ring the sealant will squish inward even further than the OD of the o-ring, and cure in that position. So especially with HD oversized studs, I keep worrying about possibly restricting oil flow to the cam journals.

I could see giving them a light rubbing of the same oil you'll use in the engine, especially if that engine might sit for awhile before it gets run. In my case, I'm guessing it will be at least mid-Summer before I have a chance at doing more than cranking it with the starter, so it seems like a good preventative measure to keep the O-rings from drying out... not that they *should* in just a few months, but I would think the oil on them would just ensure that?

The NOS Kaw o-rings I used were in the same original dried out plastic wrapper that someone had carefully placed them. They could have been sitting in there for thirty years, but were still good when I put them in dry. I may even have washed them with soap and water to get them squeaky-clean. That was early 2015, and at least 12k hard-ridden miles ago..
If I ever need to do it again, I'll remember Jeff's advice, since his way worked better than any of my previous attempts had. In fact, I saved the phone message he left on my answering machine, just so I wouldn't forget. :lol:

Old rubber is never good in any application.