How to install oil orifice?

[Rocketman]

Getting ready to install rebuilt heads on my GL1000 and am puzzled about the oil orifice installation. The O-ring on the smaller end of the orifice fits into the hole in the engine case just fine, but the O-ring for the wider end does not fit into the hole in the head (see pics). I don't think they intended for the O-ring to sit above the head surface as it would interfere with the head sitting flush on the engine case when I torque it down. I tried pressing the O-ring down around the orifice into the hole but it didn't seem that was correct. I may have been able to force it in but I didn't want to risk damaging the O-ring. I went to the Honda dealer and confirmed these are the correct O-rings. The picture diagrams just show an exploded view which doesn't show the final location of the O-ring.

Anyone know how this is supposed to be? Would appreciate any help. Assembly on hold until I figure this out.

Mike

[thrasherg]

I hope someone with some knowledge can reply, but you must have a head gasket that goes between the cylinder and the head, so the o-ring is not being completely squashed, it just has to compress to the same thickness as the head gasket.. If you place the head gasket on the cylinders, is the opening around the orifice large enough to accept the o-ring? If yes it probably means the o-ring does go there.. Just an idea..

Gary

[Rocketman]

Hadn't thought of that. I'll check it out and post.
Mike

[Rocketman]

Gary,

Looks like you could be right - see pics below.

Pics 1 and 2 show the head gasket on a white paper to clearly show the gasket opening. Pics 3 and 4 show the head gasket laid in position on the head. The O-ring does fit nicely into the opening in the gasket so it looks like that's how it is designed.

There is one thing I'm curious to know. If the large O-ring by itself provides the seal between the head and the case, what is the purpose of the small O-ring on the oil orifice? It seemed to me the orifice bridges the gap between the head and case in which case O-rings at both ends make sense, but an O-ring on one end ....?

If anyone knows for sure this is how the O-ring is installed please let me know.

Thanks,
Mike

[thrasherg]

It sure does look like the o-ring is meant to go there, but as you say it would be nice to have someone that has worked on their engine chip in and confirm! All the best.

Gary

[Old Fogey]

You have the oiler and the O rings correct. Remember that the oil is being fed at anything up to 75psi. The large O ring is to prevent oil being forced into the head gasket; the small O ring to prevent oil being forced back down the outside of the oiler.
Yes, to some extent it could be viewed as a 'belts and braces' job.

[Rocketman]

Old Fogey,
That's kind of the conclusion I came to. Its nice to find out for sure before mounting the heads.
Thanks, Mike

[Fred Camper]

You helped us all learn Rocketman.

[Rocketman]

To Old Fogey and anyone else,

Not to beat this to death, but I just remembered something that makes me wonder if they were installed correctly to begin with.

When I took the heads off and removed the oil orifices there were metal pieces inside the right orifice and inside the case oil passage where the orifice came from. I think the metal had been in there for some time (decades?) because I strained the oil, examined the oil strainer, and dissected the oil filter and there was no metal any where else.

The pieces were large enough that they couldn't pass through the small holes in the small end of the orifice and were trapped inside the orifice. I had to use the smooth end of tiny drill bit in the small hole to push the metal pieces out. The only way I can see that the metal could have got inside the orifice is if the large end was facing toward the engine case. That's opposite of how the illustrations in the parts manual show. Both the illustrations for the left and right head show the large end toward the head, and the illustrations of the large and small O-rings support that as well.

Judging how worn the valve guides were I doubt the heads have been off since Honda put it together. It's hard to imagine Honda put them in backwards, so is the parts illustration wrong? I already have mounted both heads so I hope I have it right. I'm ready to continue putting the cams in, etc., but this has me wondering.

Any thoughts on this? If anyone has a Clymers or Haynes manual I would be interested to know what that says.

[Old Fogey]

The illustrations are correct; the way you have them fitted is correct. If you try to fit them the other way round, the heads will not sit down on the cases.

[triketrash]

Too bad I didn't see this 24 hours ago- I'm putting the head back on my bike and only put the inner o-ring on the oiler. Outer one didn't make sense to me so I didn't use it. Is this gonna foul things up? I'd hate to have to pull everything apart again, but I will if I have to. I guess my nice new head gasket is toast if I DO have to take apart huh?

[Old Fogey]

Well, we have successfully re-used gaskets that have not been put through a heat cycle, but you can't rely on that always being the case; we also have had failures doing that. It's your call really, but you do need to pull the heads and fit that O ring.

What would I do? I'd go for it. Make sure that you moly grease the threads and underside of the head of the head bolts and torque it down in the correct sequence to the correct figure.

[vico]

Hellos friends, I'm looking for a couple of "oil orifice" (12238-371-000) and I couldn't find them anywhere. Does anybody knows where can I buy them? or the part measurements to make a reproduction? Thank you.-

[83 MUTT]

gettin ready to install the right head on my 82 1100 and i cant find one of the orifices,so i took one out of a 86 1200, its different, it has holes around the small end where the 82 doesnt. can i use the 1200 one?? there also different part numbers

[Old Fogey]

I'm guessing that, because the 1200 has hydraulic tappets, it needs a higher oil flow to the heads. The 1200 pump is also driven faster and so also has higher flow.
So where does that lead? Hmm....you would have higher flow to the head but probably lose a bit of pressure elsewhere. At higher revs that would not be a problem but there is only about 5-8psi at idle.
If no-one nearer can help you, come back to me as I have a couple of spares.

[83 MUTT]

you have the 1100 ones??

[Old Fogey]

The 1100 are the same as the 1000. Yes, I have spares.

[83 MUTT]

except 83's..............83 on the left( i just took the head off),86 1200 on the right

[83 MUTT]

82 on the left...83+ on the right

[Old Fogey]

Well now, here's a puzzle!
I know for sure that the ones in my 76 engine are the same as your original, without the side holes. But the two spares that I have, which came out of GL1000 engines, have the holes. Furthermore, the Honda Fiscs show the holey ones right through all the four cylinders, as part 12238-371-000.

I can only assume that the part was changed very early on and the same part number used. That is not usual Honda practice, there is usually a modified suffix, but I have seen this before.

So the long and short of it it, use what you have!

[83 MUTT]

just got a set of 76 heads with these in um...... done lookin around for the ONE i have.