Topic: sohc4 o-rings

[aglick87]

After much trouble finding o-rings to go between the block and head for the oil galleries feeding the cam assembly.  I did find some at lowes in the plumbing section.  I took them home and fitted them up and they looked as if they would do the job.  So I put the block on, along with the head and torqued everything down.  Two days later, I was talking to a friend and he asked me if I put high temperature o-rings in it.  I told him that regular ones were in it.  He told me that this would probably not work as regular rubber rings cannot withstand the engine heat.  What do you guys think?

[MRieck]

I think it will be just fine.

[apr1967]

I'd like to replace the orings on my 79 650.  I'm tired of the oil stink and stain.

Someday (not today) I want to do a full restoration, but for now I just want to improve on it.

What orings at HD did you buy (size) and did you replace the head gasket at the same time?  How difficult was the install?

[aglick87]

well, finding a metric o-ring in the U.S. is next to impossible. I went with a ring that had an outside diameter of 7/16ths and a thickness of 3/32nds.  The second measurement is the important one.  You want a ring that is thick enough to sit down in the groove in the block and still clear the gasket enough to seal against the head when torqued down.  I looked my ring up on powersportspro.com.  The specs on my bike called for a ring with a thickness of 2.5 mm, which is 100 thousandths of an inch.  When I measure the thickness of these 3/32 rings, it actually measured out at 108 thousandths.  So it worked out fine.  The job itself wasn't all that hard.  The hardest part was cleaning the gasket material off.  As far as replacing the gasket, A MUST.  Don't ever reassemble a motor without a fresh gasket.  Especially a head gasket.  You can proabably pick up a top end gasket set somewhere online that will only give you what you need to do the job.  Hope everything works out. 

t

[apr1967]

You would think that a top end gasket set would include the Orings, wouldn't you?

So while I am at it I might as well pull the cylinder and see what she looks like (maybe stuck rings) and get a head job done, eh?  (I'm adding work, ick).

BTW, I have a rubber and Nitrel oring set that I bought at Harbor Freight.  I might have Nitrel orings that are the right size, probably a better match for this job..

[MRieck]

You would think that a top end gasket set would include the Orings, wouldn't you?

So while I am at it I might as well pull the cylinder and see what she looks like (maybe stuck rings) and get a head job done, eh?  (I'm adding work, ick).

BTW, I have a rubber and Nitrel oring set that I bought at Harbor Freight.  I might have Nitrel orings that are the right size, probably a better match for this job..

Top end kit includes all orings (OEM Honda kit). Go nuts- bore it out, port etc.