Author Topic: Resealing Cases tips? (Read 4071 times)

danarchy77550f · « **on:** January 12, 2014, 04:00:29 PM »

im getting into the rebuild phase and its time to put the cases back together. i have some yama bond on hand and ive thoroughly cleaned the machined surfaces. How much should i put on and do i need to hit the areas where the crank journals are?

danarchy77550f · « **Reply #1 on:** January 12, 2014, 04:01:08 PM »

it is a 1977 CB550F

jtb · « **Reply #2 on:** January 12, 2014, 04:41:19 PM »

light coating

bjbuchanan · « **Reply #3 on:** January 12, 2014, 07:58:05 PM »

When I did mine I did a very light smear on the outer lip of the case. I did not run a bead because when assembled the cases should be flush, the sealer has to squeeze out somewhere right?

That is also why I do the smear more so on the outer lip, less crap potentially in the tranny/lower end. The non hardening sealer is the way to go but I still like to limit what does get it

dave500 · « **Reply #4 on:** January 13, 2014, 12:56:10 AM »

none on the journal mating surfaces.

PeWe · « **Reply #5 on:** January 13, 2014, 02:52:31 AM »

Very, very thin layer on both surfaces is what I have done to be sure. While doing it I'm thinking about NO sealer squeezing out on the inside that later on can fall off into the oil and block the thin oil passages in the head. My experience is CB750 SOHC.

Last time with Honda Bond. I think its the same as Kawa or Yamabond.
Before that with leaking Hylomar that a friend told me will cause a leak. I did not listen and got small leak making the engine dirty.

Before that I had very good experience with Golden Hermetite that always sealed where ever I used it. I have a tube of that in good shape purchased 25 years ago, today not available when It's too good... smell of methylene chloride, a very good chemical for removing paint

lucky · « **Reply #6 on:** January 13, 2014, 10:29:39 AM »

Instead of using a "Copy Cat sealer like Yama Bond, or Honda Bond why not just use the real thing.
GASGACINCH.

DO NOT USE products made for cars!

Clean the mating surfaces of the crankcase with acetone.
Apply a thin coat of Gasgacinch to each side. Carefully assemble.

NEVER put Gasgacinch or anything else on a crank journal!

If Gasgacinch squeezes out a little you do not have to worry. It is like a rubber band when you remove it. It all stays together. Squeeze out will not fall into the inside of the engine.

MRieck · « **Reply #7 on:** January 13, 2014, 11:10:44 AM »

Tha's interesting about not using sealer on the main bearing saddles. I have done it many times and it is recommended in many factory manuals. The manuals in general say to keep the sealent 1mm away from the saddle edge.
I do know people who have experienced oil leaks without using sealer.

flybox1 · « **Reply #8 on:** January 13, 2014, 11:18:00 AM »

For my own edification...why would you NOT want to apply a tiny amount of sealer to the journals?
(I'm using HD studs here, and am leaning towards using it, more so for leak prevention than sealing)

dave500 · « **Reply #9 on:** January 13, 2014, 11:36:12 AM »

if your talking about this type of area,they dont actually seal anything on the 500/550s.

jtb · « **Reply #10 on:** January 13, 2014, 06:00:38 PM »

I put a light coat of three bond 1104 on the journals, too.

lucky · « **Reply #11 on:** January 13, 2014, 07:14:41 PM »

Quote from: dave500 on January 13, 2014, 11:36:12 AM

if your talking about this type of area,they dont actually seal anything on the 500/550s.

YES...I would put a little sealer on those areas marked in RED. Just not on the bearing journals.

lucky · « **Reply #12 on:** January 13, 2014, 07:16:31 PM »

Quote from: jtb on January 13, 2014, 06:00:38 PM

I put a light coat of three bond 1104 on the journals, too.

How will the bearing shells fit now?? That sealant can be .001 thick? Bad Idea.
You need to remove that stuff from the bearing journals!

dave500 · « **Reply #13 on:** January 13, 2014, 07:19:23 PM »

you dont want those areas in red to leak lucky?

23tbucket · « **Reply #14 on:** January 14, 2014, 05:44:24 PM »

Hmmm, I would put sealant on those "red" areas as well...not for the sealing effect, but just to keep the inside of the cases from warping down lower than the outer edges. The sealant does take up space...I don't know how much, but .001" was mentioned.

dave500 · « **Reply #15 on:** January 14, 2014, 05:51:19 PM »

the sealant fills minute flaws in the surface only,you wont warp cases by not aplying it here,feel free to put there though if you feel oil will leak down the underside bolts?,just dont let it get on any bearing surfaces,itll ooze out around and into places you cant see then.

MCRider · « **Reply #16 on:** January 14, 2014, 05:52:56 PM »

First hand experience: Gasgacinch, the universal favorite, should be used on the journal saddles. I don't think anyone seriously means they put sealer on the journals.

What will happen without, oil wicks into the mainbearing stud holes and leaks down the bolt, or stud, and leaks. Very disappointing.

per Mike's post. I used some sealer but not with due care. A few of my studs are leaking. I hope to get them sealed up with bandaids short of pulling the engine.

bytio · « **Reply #17 on:** January 14, 2014, 11:51:55 PM »

Hondaman recommends putting the sealer in those areas if the bearings are new, if re using bearings then no need to.

MCRider · « **Reply #18 on:** January 15, 2014, 05:50:01 AM »

Quote from: bytio on January 14, 2014, 11:51:55 PM

Hondaman recommends putting the sealer in those areas if the bearings are new, if re using bearings then no need to.

Reference? Book? Thread?

bytio · « **Reply #19 on:** January 15, 2014, 06:00:51 AM »

If you search for Hondaman on here he has many threads, also his book "My Honda750" is a must for any owner, it is on the CB 750 however things like this are common to both.

MCRider · « **Reply #20 on:** January 15, 2014, 06:07:07 AM »

Quote from: bytio on January 15, 2014, 06:00:51 AM

If you search for Hondaman on here he has many threads, also his book "My Honda750" is a must for any owner, it is on the CB 750 however things like this are common to both.

Yes, I know. I have the book, and have dealt with Mark on many things.

I was just wondering where you saw him say that he would put sealer under the shells. Or did I mis read you?

bytio · « **Reply #21 on:** January 15, 2014, 07:58:09 AM »

I PM him when rebuilding my 750 F2 and asked your question, he quoted technical specs and gave me advice to put Honda Bond 4 on around the areas you show but to be careful not to get any on bearing surface. This was for new bearings, for older ( in spec) bearings the not putting sealer on these areas is ok. Hope that helps, it all seemed to work well for me no leaks and smooth running.

MCRider · « **Reply #22 on:** January 15, 2014, 08:04:10 AM »

Quote from: bytio on January 15, 2014, 07:58:09 AM

I PM him when rebuilding my 750 F2 and asked your question, he quoted technical specs and gave me advice to put Honda Bond 4 on around the areas you show but to be careful not to get any on bearing surface. This was for new bearings, for older ( in spec) bearings the not putting sealer on these areas is ok. Hope that helps, it all seemed to work well for me no leaks and smooth running.

Personal response. pretty good reference, thanks. I did misread your earlier post.

So it all makes sense. Enjoy your "no leaks".

BPellerine · « **Reply #23 on:** January 15, 2014, 07:31:15 PM »

took my 78 engine down and saw very little residue sealer on the mating surfaces but could see that it had been applied cause it ran down the inside of the cases ,a brown colour.engine had never been apart.nothing by crank journals and motor was dry.bill

MRieck · « **Reply #24 on:** January 16, 2014, 04:48:53 AM »

Quote from: BPellerine on January 15, 2014, 07:31:15 PM

took my 78 engine down and saw very little residue sealer on the mating surfaces but could see that it had been applied cause it ran down the inside of the cases ,a brown colour.engine had never been apart.nothing by crank journals and motor was dry.bill

Exactly

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Author Topic: Resealing Cases tips? (Read 4071 times)