stupid head/block o-rings

sbc1320 wrote:

Are these used on the KZ900? Where are they located at?

No these are only used on the earlier "J" motors. This is why I do not think that they are that critical. Since they stopped using them again on the 1100s.

www.parcoinc.com Orings Galor.Any shop that services hydraulic pumps and valves will either have the orings you need or will be able to get them cheap.bring an old one with you.or measure ID,OD and cross section.and give to the guys up at the top here

jeffasaki wrote:

www.parcoinc.com Orings Galor.Any shop that services hydraulic pumps and valves will either have the orings you need or will be able to get them cheap.bring an old one with you.or measure ID,OD and cross section.and give to the guys up at the top here

The problem is that these have an oval cross section and not a round one. That is what this whole debate is about. But I also believe that they might not even be necessary. So, just reuse the old ons.

I thought someone had posted that they were used on the KZ900's so I ran outside and looked under my covers on my engine and didn't see them. I already have the cylinder and rings installed. Thanks Otakar, I was starting to get very nervous.

My 1983 KZ1100 Spectre has them.

KZ1100 Bully wrote:

My 1983 KZ1100 Spectre has them.

I believe that that is the last "J" series motor that uses them. The ZN and ZX series motors no longer do, even though they are otherwise pretty much the same as your motor. When I rebuilt my 81 CSR1000 motor I used the top end from a 83 GPz1100 and it no longer had these "O" rings.

All you need is a oring that will provide around .015 to .020 thou of squish and fill the space required.Viton is best.std orings come in 0.100.200 300 ect series.Metrics are measured in mm.I would never reuse a oring Ive seen to many $100,000 dollar peices of equipment fail in the field after installation for just that reason.PAIN in the ass and want to kill the guy that did the rebuild.(if its there when i take it apart i want there when i put back together)If using Buna id go with 90 durometer.

jeffasaki wrote:

All you need is a oring that will provide around .015 to .020 thou of squish and fill the space required.Viton is best.std orings come in 0.100.200 300 ect series.Metrics are measured in mm.I would never reuse a oring Ive seen to many $100,000 dollar peices of equipment fail in the field after installation for just that reason.PAIN in the ass and want to kill the guy that did the rebuild.(if its there when i take it apart i want there when i put back together)If using Buna id go with 90 durometer.

These "O" rings were only used in 1981-1982 and some 1983 engines they were not used in the earlier engines and they stopped using them again in the ZX series engines in 83. From 84 on they were not used at all. There must be a reason that they were so short lived. The only exception to this rule are the police bikes. The engines in all of those was of the complete 1981 design.

By the way, just to make things a little clearer. As I indicated before. "Viton@" is a trade name. This material is commonly called Fluorocarbon rubber. It can also be found under the names of, Fluorocarbon, Viton@, Fluorel@, Kalrez@, and Kel-F@. These are the same materials, and are all just as good.

jeffasaki wrote:

All you need is a oring that will provide around .015 to .020 thou of squish and fill the space required...

Overall I agree - but with a big caveat. You must ensure the o-ring doesn't encroach on the oilway. If it does you can reduce oil flow. On an o-ring like this, I wouldn't want to take a chance on a regular round cross-section.

Old Man Rock wrote:

"I was worried that they would be hard and crappy, but they were like new.".... :laugh:

Damn big man, I swear you're going to be gray/bald by the time your finished with this build.... :laugh: :laugh:

Not if I can help it.

He'll be melting rubber this summer! :laugh:

Jeff.Saunders wrote:

jeffasaki wrote:

All you need is a oring that will provide around .015 to .020 thou of squish and fill the space required...

Overall I agree - but with a big caveat. You must ensure the o-ring doesn't encroach on the oilway. If it does you can reduce oil flow. On an o-ring like this, I wouldn't want to take a chance on a regular round cross-section.

Than why are these "O" rings on so few models and not on older or newer ones?