Topic: 1978 CB750K — Post 836 OIL PRESSURE - not good

[SKTP]

Modified the old rear turn signal brackets to work with the new LED signals (the grab-bar uses the fender-mount-holes they use to go in)...still needs some work, but I'm thinking it's going to look good

[SOHC4 Cafe Racer Fan]

It's coming along, Chris! I bet you cannot wait to get the APE parts.

[SKTP]

Got my Transmission back! Spent the weekend cleaning mating surfaces and other odds and ends

QUESTION: I had my cylinders honed about 300-400 miles ago (rebuilding due to a leak) should I get them honed again? There is some carbon in them from my terrible valve seals (which have now been redone by APE) or should I just clean them with Scotchbright or something (there's not a lot). Could rehonning remove too much material?

[70CB750]

If you are reusing your rings and kept them where they were there is no need to hon.

[SOHC4 Cafe Racer Fan]

Chris,

No need to re-hone with so little miles.

[SKTP]

So I thought this weekend was reassembly weekend...but...if you can see that one primary chain has more slack than the other....I'm guessing new primary chains are needed. This bike came with a broken speedo with 71191 miles on it...no sense cutting corners now

I guess I'll replace all the internal shaft bearings while I'm at it...

BOOK MARKING

yes. 
be detailed in your cleaning of the caliper.
any pitting in the piston surface can compromise proper function.
(replacement Phenolic pistons are readily available)

read this before you assemble anything...

http://forums.sohc4.net/index.php/topic,56544.0.html

This thread has gotten very confused.  Lets' review.
There are four products needed to restore a caliper.
1. Brake cleaner
2. Brake parts assembly lube for the caliper seal only.
3. Dow corning High vacuum grease.
4. Brake fluid

Each has it own specific application and needs for the task to be performed.

#1 is used to get everything clean.  (given the confusion, it had to be said)
#2 is used ONLY on the seal and must be compatible with #4, as some of it will invade the brake fluid chamber.
#3 is NOT used on the seal, as that would put silicone inside the brake fluid chamber.  This is a bad thing as the compounds are incompatible.  It is used behind the brake pads and a thin coat is used on the parts of the calipers and piston that are exposed to the elements and subject to water ingression.  The Dow Grease will not mix with ANYTHING.  It is a simple barrier with the very important property that it will NOT melt when the parts get hot and then run/creep into the brake pad friction material and provide lubrication between pad and disk rotor.
#4 is what makes the hydraulic part of the brake function. (I hope that part is clear.)

The "Permatex® Counterman’s Choice® Ultra Disc Brake Lube" I have NOT used.
It is NOT to be used in the #2 application (directly on the caliper seal, as that would put some inside the brake fluid vessel and is clearly NOT it's intended application).

Depending on it actual composition, it may be suitable for the #3 task, IF and I stress the IF part, it will not melt/run into the brake pads.  The brake pads/rotor interface are where you WANT fiction!

Previous discussions in this forum were regarding Syl-Glyde, which I have personally tested and can pretty much guarantee that it will run/creep into the pad to rotor interface.  It only contains silicone as a minor ingredient.  The rest of this (Syl-Glyde) compound cannot take the 500F plus heat that the Dow corning grease can without doing a phase change.

The remaining question is whether Permatex® Counterman’s Choice® Ultra Disc Brake Lube will run/creep into the brake pads/rotor, especially when it gets hot, in this application on the Honda brake caliper.
I don't have any, I haven't tested it, you use it at your own risk.  I do know the Dow corning silicone grease DOES work properly and certainly appears to be the same stuff Honda used during production assembly.
I admit I am skeptical.  The last time a counterman recommended a product for #3 application, it was Syl-Glyde which, if he were still working behind the counter, I'd be tempted to make him eat.

[SKTP]

I just hondabonded the cases together. I think I was a little heavy handed. There's a small visible bead that smooshed out along the seams....if that bead gets in the engine (I'm guessing it will). Am I screwed or is some extra hondabond normal and will get taken out by the oil filter...

[MCRider]

I just hondabonded the cases together. I think I was a little heavy handed. There's a small visible bead that smooshed out along the seams....if that bead gets in the engine (I'm guessing it will). Am I screwed or is some extra hondabond normal and will get taken out by the oil filter...

That's why you use non-hardening sealer like HondaBond. The ooze will usually get tacky and stay put. The hardening silicone based sealers, the ooze gets hard, breaks off and clogs the oil lines.

IMO, you should be OK.

[SKTP]

Here's the bead viewed through the piston hole

[timbo750]

I just put my cases together last weekend and got the same bead.

[Tintop]

That doesn't look excessive, it's when you have large blobs hanging to the inside your in trouble.

[SKTP]

Cases are together. Jugs are on. Finger's crossed there's not too much Hondabond....getting closer

[SOHC4 Cafe Racer Fan]

Cases are together. Jugs are on. Finger's crossed there's not too much Hondabond....getting closer

I think you are okay with that amount.  Also, Hondabond is not as loosey goosey as RVT; the Hondabond squeezed out should stay put.

[SKTP]

I have not put the head on yet...worst case scenario, if there is too much Hondabond? Is that a common failure?

Please note: I am a worrier in general

[MCRider]

I have not put the head on yet...worst case scenario, if there is too much Hondabond? Is that a common failure?

Please note: I am a worrier in general

I'm not positive about HondaBond, but if it says "non-hardening sealer" on the can, failures are not common, nearly unheard of. And overdose of sealer was not the culprit.

If it says "silicone" on the can, failures are more common though not absolute. And quite frustrating.

[SKTP]

http://www.amazon.com/Hondabond-High-Temp-Silicone-Liquid-Gasket/dp/B006YTTV4W

• High-Temp formula is good up to 600 degress farenheit
• For use in areas not requiring a solid gasket, such as cylinder head covers
• Dries quickly, remains flexible, resists vibration
• Resists oil, water, and most chemicals

[MCRider]

http://www.amazon.com/Hondabond-High-Temp-Silicone-Liquid-Gasket/dp/B006YTTV4W

• High-Temp formula is good up to 600 degress farenheit
• For use in areas not requiring a solid gasket, such as cylinder head covers
• Dries quickly, remains flexible, resists vibration
• Resists oil, water, and most chemicals

I would have preferred that it didn't say "silicone " on it, but maybe things have changed since my encounter. Anyway, it does say "remains flexible" and that's the main thing. I read all the reviews (skimmed them anyway) and no encounters with the dreaded hard silicone bits that plug oil holes. I still vote that you are OK.

[SKTP]

Just updating my thread:

I used Hondabond HT on my cases. Have since learned that Silicon is not ideal for that application. Have to rip it all apart again and use proper sealant.

Had no idea there were different Hondabonds...live and learn

Question thread in the Bikes section:
http://forums.sohc4.net/index.php/topic,153545.0.html

http://forums.sohc4.net/index.php/topic,153494.0.html

[edwardmorris]

Sorry to hear dude, hopefully it will be the last time.

Question: Do you have Hondaman's book? That will/would have saved you a ton of re-work and grief....

[SKTP]

I do have his book...but, I did not see anything about Knock-pins or different Hondabonds. (Plus my bike is a K8 and there's some differences I'm guessing...but maybe I need to read more in depth? But I am following his engine reassembly line by line...the MLS gaskets and the Knock-pins are not covered (which make total sense) BrandEn's thread helped a lot as well

http://forums.sohc4.net/index.php?topic=107040.0

It's all good...as I said the head had not be put on yet...so really other ant gasket cleaning, it's pretty mellow to tear back again.

Plus, even though I have put the cases together 1 time before this...when they say the smallest amount of gasket sealer, they really mean it...I thought I put a thin layer on this time, but I guess it needs to be even thinner

Maybe the HT stuff would have been OK, but I'm not risking it after all of this

[edwardmorris]

OK cool, yea, specifically there is good info on the sealants to use, their setting times and how to apply and stuff which I'm guessing is pretty common across the models. The top-end however like you said, needs the additional info gems from Branden's write up. For the lowers, if you missed it before, make sure all mating/contact areas get a bit of Hondabond, just saw a thread somewhere where the crankcase bolts were leaking oil because sealant wasn't applied to the inner areas, one more potential leak to avoid while you have it apart.

[SKTP]

On that topic...I had made a post asking about just that

I am just about to seal my cases back together.

This is a page from Hondaman's book. In the book the grey (hondabond) and grey (case mating surface) is fairly difficult to see what gets Hondabond and what doesn't.

I am thinkign it is just the ORANGE areas?

I included the other colors so you guys can chime in and easily say "make sure you seal the green section too!!!"

Or if Hondaman tells me exactly where it goes, I'd happily make a really nice version of this that clearly shows the idea sealant locations

This video shows it going everywhere

Thank you all very much for you insight

[SKTP]

And we are back to this stage again — hope to re-clean and re-close the cases this weekend...practice make perfect

Still confused by the photo above if anybody wants to chime in...It's very difficult to see the grey on grey Hondabond in the the Hondaman book

[SOHC4 Cafe Racer Fan]

Chris,

Did you decide to change your stock pegs to rear sets?

[SKTP]

Nope...I have thought about it, but I don't think for my height, that it really does anything for me...at this point I just want to get it back together...maybe down the road