Author Topic: 76 CB750K engine rebuild thread - With Video!  (Read 12428 times)

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Offline dilbone

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Re: 76 CB750K engine rebuild thread - With Video!
« Reply #75 on: July 22, 2009, 11:19:23 AM »
wow, just read this whole thread, not sure how I missed it.

Amazing job, hope you get all the little bugs worked out...and hope it cools off soon...

Peace

Offline michrobi

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Re: 76 CB750K engine rebuild thread - With Video!
« Reply #76 on: July 22, 2009, 06:06:23 PM »

Funny, after you are sure you've tried everything, you start trying the stupidest #$%*. I took the little metal cable guide out of the stator cover thinking it might be messing with continuity, or causing a ground out. Started it up and have good charge.

Damn gremlins!

Another funny thing, every time I mess with the ignition it runs a little better. And always at the absolute end of the turn dial. And I notice at idle it dips for a split sec like it wants to die, then catches back up... at the very same rhythm it did before the rebuild. Every day I'm more and more sure that Martek has had it.

I considered the Cycle x power arc ignition, but the Dyna 2000 is so damn tweakable I had to do it. Should be here Friday or Saturday.
-Mike

'78 CB750F All stock except for the powerplant. Jived it off my Dad in the spring of '94. He had it since 1980 and it's the first bike I ever rode on.

Current project: http://forums.sohc4.net/index.php?topic=67756

How's them SOHC4 patches coming?

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 76 CB750K engine rebuild thread - With Video!
« Reply #77 on: July 22, 2009, 06:16:53 PM »
Take a couple days off. You deserve it.

Will the JMR stickers get there before the Dyna?  ::)
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Zaipai

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Re: 76 CB750K engine rebuild thread
« Reply #78 on: July 22, 2009, 07:00:41 PM »

Here's where I'm at...

This thing on?   :)
Question? What did you shoot into the block and why did you do that? I have never done a break down and was able to follow you until then.. Just don't know what that was.. Thanks for the journal, I want to do this to my engine next winter this will be invaluable to me when I do..!
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Offline michrobi

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Re: 76 CB750K engine rebuild thread - With Video!
« Reply #79 on: July 22, 2009, 07:24:57 PM »

The solvent blasting part with the 60cc syringe? It's Stoddard Solvent, and I did it because I had the cases glass bead blasted. There were tiny glass beads all over the place in there. had to make sure I got all the oil galleys, threads and so forth completely free of glass sand or it would have chewed up my bearings.   :)
-Mike

'78 CB750F All stock except for the powerplant. Jived it off my Dad in the spring of '94. He had it since 1980 and it's the first bike I ever rode on.

Current project: http://forums.sohc4.net/index.php?topic=67756

How's them SOHC4 patches coming?

Offline Zaipai

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Re: 76 CB750K engine rebuild thread - With Video!
« Reply #80 on: July 22, 2009, 08:16:22 PM »

The solvent blasting part with the 60cc syringe? It's Stoddard Solvent, and I did it because I had the cases glass bead blasted. There were tiny glass beads all over the place in there. had to make sure I got all the oil galleys, threads and so forth completely free of glass sand or it would have chewed up my bearings.   :)

Ah.. ok that makes perfect sense. I had a similar problem however I have points and it turned out I had the stupid wires swapped, the blue lead going where the yellow one should go etc.. once I swapped them out it made all the difference. Well hope the Dyna 2k gets it all sorted out for you. This is one awesome post I will be referring back to. Thanks so much for doing it. 105 degree heat and all for us it was worth it. Even if it does not seem so for you...
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Offline michrobi

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Re: 76 CB750K engine rebuild thread - With Video!
« Reply #81 on: July 22, 2009, 10:30:26 PM »

Just got back from a 30 minute ride up around the foot of the canyon. It rolled at 4200-5000 RPMs without any major complaints. All I did was put the new shocks on and start it up. I was just going to cruise around the parking lot like usual, but it was running so clean I took it out on the road and kept going. 17 miles on the old odometer and counting.

That has to be the most relaxing ride I ever took on a motorcycle. 10:30pm, 77 degrees and very little traffic. Perfect.    8)
-Mike

'78 CB750F All stock except for the powerplant. Jived it off my Dad in the spring of '94. He had it since 1980 and it's the first bike I ever rode on.

Current project: http://forums.sohc4.net/index.php?topic=67756

How's them SOHC4 patches coming?

Offline Simpson

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Re: 76 CB750K engine rebuild thread - With Video!
« Reply #82 on: July 23, 2009, 08:11:34 AM »
Awesome thread! I don't know how I missed it this long. Congrats
1970 CB750 K0
1975 CL/CB 360 Mix

Offline michrobi

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Re: 76 CB750K engine rebuild thread - With Video!
« Reply #83 on: July 23, 2009, 12:53:36 PM »

I was planning to use 2.2 OHM coils on that... Do I want the 3.0 OHM set instead? What's the difference?
-Mike

'78 CB750F All stock except for the powerplant. Jived it off my Dad in the spring of '94. He had it since 1980 and it's the first bike I ever rode on.

Current project: http://forums.sohc4.net/index.php?topic=67756

How's them SOHC4 patches coming?

Offline michrobi

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Re: 76 CB750K engine rebuild thread - With Video!
« Reply #84 on: July 31, 2009, 10:24:47 AM »
The engine never looked back after that first 30 minute cruise, and continued to run better every ride. I hit 496 miles when I rolled into work today, so the trip home tonight will mean the break in is complete. It runs strong through 5k RPMs. I'll finally get to run above 5000 tonight after the oil change. I can't wait.  :D

I got my 3.0 OHM coils for the Dyna, and have every intention of throwing that in this weekend. I am also inclined to move from 115s to 120s on the Mikuni 29mm smoothbores.

I think that the break-in having been completed means this thread can come to a close. In conclusion;

Gaskets are fragile and require meticulous, careful handling and placement.
Cardboard bolt patterns to hold the bolts are worth more than words can describe.
30 year old electrical connections must never get the benefit of the doubt.
Don't be afraid to do anything. Common sense is usually right.
Don't let yourself look for excuses to not work on it.
Whatever you 'think' you'll spend, double it.
Frustration is the enemy. Take a break, come back and work on something else for a bit.
Don't get discouraged. Get out there, turn some tunes on and keep rolling. Go... cmon get going.
July is not the month your rebuild is looking for <Jedi hand gesture here>.
And finally, a moment of silence in sincere appreciation of Harbor Freight. <Hat off>

Now let's see here, where'd that Cobra end up.....
« Last Edit: July 31, 2009, 04:52:32 PM by michrobi »
-Mike

'78 CB750F All stock except for the powerplant. Jived it off my Dad in the spring of '94. He had it since 1980 and it's the first bike I ever rode on.

Current project: http://forums.sohc4.net/index.php?topic=67756

How's them SOHC4 patches coming?

Offline Caminokid

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Re: 76 CB750K engine rebuild thread - With Video!
« Reply #85 on: July 31, 2009, 11:08:25 AM »
The first 750 I rebuilt was my brothers 77 750K. He had a flat and his wife wouldnt let him buy a tube for it. It sat behind his house for 2 years. He went and got a tube for it...got it on there and went to start it...found out it was locked up. This was in 82. He bought the bike new. I was 14 when I tore it down. I had been rebuilding alot of dirt bikes at the time. I went through what you did. I know the feeling. After the first one...you never forget. The next one will be easier. After the 750 I was on a 450 kick...the 65 to 74 450's. Then onto building performance 450's. 450's that would run with any stock 750. Then a 77 SS came into my life. Had to tear it down and make it run. I mean really run! That was in 84.  I loved that bike. Wish i had it back.

Good job on your bike.
God created man...Winchester and a baseball bat made then equal. Evel Knievel