Topic: brandEn's leak free top end thread = Tips, Tricks and Suggestion encouraged

[grcamna2]

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[Translations]

Just wanted to thank brandEn for making this post! I followed all the steps listed and my freshly rebuilt 750F engine just passed 200 miles the other day and is indeed leak free as advertised  Seriously though really appreciate this thread, hard to find information especially for the 77-78 super sport engine.

[bigutah]

I’ve recently created a step by step video on rebuilding my top end Using this post. It will drop this week. I can testify that after riding the pacific coast highway from San Fransisco to Portland, it’s leak free.


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[Ellz10]

                                         *** WARNING ***
When installing the two cylinder studs with the oil feed holes be sure not to plug the small oil feed holes with loctite. Apply the loctite with a toothpick, and very little of it. Once the two studs are installed blow compressed shop air in the oil gallery via the oil pressure sensor hole. Verify the holes are clear by the air that shoots out of the stud oil holes! Making sure the holes are not plugged is VERY VERY important.
_________________________________________________________

This right here quite literally saved my rear... and alot of regret, disappointment, and hours!

One of the two holes was blocked and I never would've thought to check to make sure they're clean and clear, so a great many thanks to you!

[Ellz10]

Once the jugs are installed time for the head! Not much to say. I installed a VERY THIN layer of gasgacinch around some of the oil holes and cam chain tunnel.









Once the head is set torque your nuts! Ape recommends 20-22ft lbs for THEIR heavy duty studs. Make sure to follow the tightening sequence stated in the Honda manual.

I also recommend tightening everything in a three step process.


First Torque= 7 ft lbs
Second Torque= 14 ft lbs
Final Torque= 20-22 ft lbs





Now once everything is buttoned up. It was recommended to me to let the head sit for 24 hours. After 24 hours recheck final torque. I did this and everything was still tight.


After everything is good to go time to install some rubber pucks. These are a big source for oil leaks because they lead right out to atmosphere.


peek-a-boo!






I used Hylomar on my pucks



install your pucks, clean up the residual that squeezes out, and then install your cam towers!


Other tips I can offer,
-Check all your head threads. Heli-Coil any damaged ones. The soft aluminum pulls threads easily.
-Inspect your valve tappet adjuster screws. The tips can get damaged from years of use.




If anyone has any more suggestion please chime in. Also if anything I have posted is incorrect please let me know!

This may be a dumb question, but when using aftermarket HD studs and nuts (mine are Kibblewhite), are the washers still being used under the head nuts? It makes no mention of the washers in my installation instructions so I just want to clarify...

[Alan F.]

Yes, still use the washers with HD studs.

[Ellz10]

Yes, still use the washers with HD studs.

That's what I thought, but just wanted to make sure.

However, now I have another question and it's irksome. So I tightened all my cylinder studs the same torque spec, in the appropriate sequence and I've found that after I followed the correct sequence for tightening down my head nuts, most of the tips of the studs come thru to what I imagine is the correct spot, whilst some of the tips only go about 3/4 of the way thru. Is this a problem or is it acceptable? They were all tightened to 22 ft lbs as per the instructions from Kibblewhite.

[Alan F.]

Ooh, that question is above my pay grade. Perhaps ask in the high performance section?

[Ellz10]

Ooh, that question is above my pay grade. Perhaps ask in the high performance section?

Good idea!

[rollypoli]

Is there a guide like this for splitting and rebuilding the bottom end. I can’t seem to find one

[PeWe]

Honda CB750 Shop manual.
Available as download in pdf. See manuals and diagrams section.

Also possible to order a paper copy.
https://www.ebay.com/itm/251652308622?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=8uuBLBV_Q4y&sssrc=2349624&ssuid=XgCEg0CPSya&var=&widget_ver=artemis&media=COPY

[BenelliSEI]

Just re read this as a good reminder for my next top end build, coming soon. EXCELLENT PIECE.