Topic: Seals on studs

[70CB750]

The F engine, when I took it apart, had rubber seals on studs under cylinders.  I don't mean those two o-rings for the oil flow, these seals were on other studs.

I understand it was Honda attempt to keep water out:

Cyclex:  As great as Honda is and was...
…A mistake was made.
4 cylinder studs are exposed through the fins in the head which could allow dirt and road debris to enter the lower end.
Honda tried to correct this problem by putting large “O” rings at the bottom of the studs to prevent water and debris from entering the motor.
Here is what we do…….Drain holes are drilled and honed to accept brass tubes. Brass tubes are pressed into place and problem solved.

What can i do about it except sending it to CycleX,  use fresh seals?  What seals and where from?  The fiche does not list them.  Anybody dealt with this problem?

Or I could drill  drain holes, but where?

[CB750F2]

Replace the seals. If you cannot find the correct part number you will be able to buy a suitable O ring from your local O ring supplier. Some one will chime in with the correct size I am sure. I also suggest that you read through topic 84658. CycleX feature in that topic. Tomorrow I will have a look in my parts fiche. The O rings may not be identified in the cylinder page but they may be identified in the crankcase page. Pat

[70CB750]

Thank you.  I was under - wrong - impression, that the CycleX solution is to provide a drain for the accumulated water in the jug stud hole.  After reading the 84658 I seem to understand that they mean sleeving the stud hole with brass tube; I may have that done localy too.

But I am just theoretizing now, gotta look at the head and think about it.

[CB750F2]

The part no for the o ringsl is 91301-410-000. I don't know the availability from Honda but the description says "O-ring 5.5x3". Pat

[bjbuchanan]

It is a cute marketing approach but bottom line I bet a nice viton o-ring of the correct size and squish you could save having to pay for machining stuff. It seems like a lot of early engines made it through life without the sleeves

Not to say that O.E. never has room for improvement, I'm just saying that there are plenty of other solutions to that particular "issue" IMO

[70CB750]

Yes, 5.5x3 is also mentionedin the oldthread. BrandEn ended up stacking twoorings on top of each other. I will see what I can find.

Will use orings for sure and if i can find some sleeves for thehead later thats fine too.

Thanks, gents!

[70CB750]

Gotta love the local hardware store.  I found metric o-rings that fit just about perferct.  Pictured with the old squished o-ring next to it.

[madmtnmotors]

http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721

[70CB750]

http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721

Thanks Wilbur, I just took a caliper to the store. 

[madmtnmotors]

10-4. These o-rings serve two puposes:

1) to prevent water and debris from enterining the crankcase (as noted in your 1st post)

and..... just as imortantly...

2) to prevent crankcase pressure from pushing oil UP this passage where it blows out all over your pants leg, mostly at highway speeds. I had so much oil on the shins of my jeans I could actually feel the heat from the hot oil. PO had failed to install these o-rings. Had to do some soul searching to convice myself to pull the head AND cylinders for what appeared to be a top-end leak.