Author Topic: Better late than never so here I am with the first of two Honda CB's.  (Read 2735 times)

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Offline PorQueNo1970

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Ciao folks! I'm a newbie and a putz with flashes of genius who's been told that I'm going through a mid-life crisis after happily taking a disassembled 1978 Honda CB750K for free and beginning the adventure of putting it back together. After some initial tear down and some copious amounts of research I thought that I should get a second two-wheeler to ride and ended up with a 1976 Honda CB550.

I've been getting the CB550 ready to ride while I slowly reassemble the 750. I'll start a new thread for the 76 CB550 rebirth/build but I thought I'd share my eagerness with you.

Here are some photos from the pickup (12/2016) to now....







So far the only thing I've done to the frame is remove the old paint, de-rusted and painted with primer to store away while I build the engine. Nothing has been modified on this yet. Probably not much will happen because the idea is to keep the 750 as a cruiser/tracker, not a cafe racer setup...


The carburetor before I rebuilt it...


After...

Oil pump...

I'm working on (but don't have pics yet) on reassembling the cylinder head. I've already verified that my new bearings for the rods and crankshaft are correct. I've got to do some more media blasting with a cheap portable blaster I picked up at Harbor Freight.

So far it's been a great stress decompression when I find the time to work on it. I'm hoping for wrapped up product in Spring of 2018.

Thanks for all the great info out there!


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Offline calj737

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Welcome! Looks like someone parked that bike in a bayou and left it for dead  :o

Really important that if you are media blasting the head, cylinders and cases, you do an exceptional job of clearing the oil galleys afterwards. Looks like you're off to a great start.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline SOHC4 Cafe Racer Fan

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Welcome! Looks like someone parked that bike in a bayou and left it for dead  :o

Really important that if you are media blasting the head, cylinders and cases, you do an exceptional job of clearing the oil galleys afterwards. Looks like you're off to a great start.

Not only rinse the blasted parts (twice) but blow compressed air through every passage/galley.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Online Stev-o

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Ciao.....subscribed to the bayou build...
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline grcamna2

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Welcome to the forum PorQueNo1970
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Can550

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Welcome to the forum. Wealth of knowledge and beauty of sharing it


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Offline PorQueNo1970

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Thanks for encouragement! It's been a blast so far.

I've got a question that maybe you can help me out with. I've researched, on this forum, having a port & polish on the cylinder head. But after looking into it, I figured it wouldn't be worth it, and the possible loss of performance, so I decided against it. In any case while refurbishing the cylinder head I found what I think are unusual mods to intake side, numbers 1 & 4. Could someone take a look and tell me if this is factory or not?




I'm not the best photographer but you can see, in the lighted area, some polishing. Is that from the factory?

I'm pretty sure this engine has an adjustable cam sprocket as well.

The guy who gave me this bundle of joy (no sarcasm intended) used to be a Honda mechanic in the 70's. They used to have a shop drag bike that they worked on Saturdays and raced on Sunday. I'll ask him tomorrow when we're back at work.


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Offline grcamna2

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Could you take another pic w/o the tape?
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline PorQueNo1970

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Could you take another pic w/o the tape?

I think it has been. Here are some more from the combustion chamber on the intake side as well. I thought you shouldn't do this?




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Offline grcamna2

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Who did the porting work ?
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline PorQueNo1970

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Re: Better late than never so here I am with the first of two Honda CB's.
« Reply #10 on: June 18, 2017, 03:26:12 PM »
Who did the porting work ?
I don't know. I just wanted to verify that it was ported before I ask the guy.

Thanks for verifying that's what I was seeing!


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Offline PorQueNo1970

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Better late than never so here I am with the first of two Honda CB's.
« Reply #11 on: August 02, 2018, 03:33:12 PM »


I’m still at!


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Offline SOHC4 Cafe Racer Fan

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Re: Better late than never so here I am with the first of two Honda CB's.
« Reply #12 on: August 02, 2018, 04:30:41 PM »
Those welds are seriously buttered on.  I guess you wanted to make sure there was little room for pinholes.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline calj737

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Re: Better late than never so here I am with the first of two Honda CB's.
« Reply #13 on: August 02, 2018, 04:34:22 PM »
You’ve made some difficult work for yourself with the welds on the inside of the pockets. Grinding those down will be tricky unless you have a Dynafile with a small radius :o

After grinding, powder the outside of the tank with talcum, and fill with gas. Any leaks will show up immediately by turning the talcum wet. This is a bit easier than a pressure test, and an easy DIY solution.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Online seanbarney41

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Re: Better late than never so here I am with the first of two Honda CB's.
« Reply #14 on: August 02, 2018, 05:35:38 PM »
The cut marks in your intake ports were done at the factory in their rushed production schedule as a mostly futile attempt at port matching where the intake spigot meets the port...this is the most obvious flow impediment that any head porter needs to clean up.
The cuts in the combustion chamber, however, I do not recognize.
If it works good, it looks good...

Offline PorQueNo1970

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Re: Better late than never so here I am with the first of two Honda CB's.
« Reply #15 on: September 13, 2018, 05:17:36 PM »


My mold for the carbon fiber seat pan!


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