Author Topic: CB750 Rebuild K0  (Read 4327 times)

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Offline 77379

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CB750 Rebuild K0
« on: January 30, 2018, 02:11:44 PM »
I saw this on eBay and asked the seller a few questions. The winning bidder never paid for it so he called me back and we worked out a deal. It was probably a better deal for him than for me. The motor is locked up and it won’t shift out of whatever gear it is in so I plan to tear it down and rebuild it. A lot of the parts and pieces are still there. The gauge shows 15,000 miles and most of the screw heads and bolts look like they have never been removed but that is coming to an end. It was set up with a fairing and bags on the back so the headlight was removed and holes drilled in the rear fender to re position the turn signals. The seller tossed those out but he still had a lot of the original tool kit. I have seen here what a many of the members have been able to accomplish and it has inspired me and encouraged me to take this project on.
Gregg

Offline Stev-o

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Re: CB750 Rebuild K0
« Reply #1 on: January 30, 2018, 03:55:43 PM »
Congrats Gregg.  She do look a little rough but that should buff right out! Ha.

I would restore it correct, the K0's are becoming very collectable and valuable.

Or ya gonna make a Chopper?!!
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline BPellerine

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Re: CB750 Rebuild K0
« Reply #2 on: January 30, 2018, 04:50:51 PM »
good project,most of it is there,so you have a good start.
1978 CB 750K ard and webers
another anfob

Offline SOHC4 Cafe Racer Fan

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Re: CB750 Rebuild K0
« Reply #3 on: January 30, 2018, 05:00:58 PM »
That oxidation will buff right out!

The good news is that you have everything there. 
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 Stev-o

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Re: CB750 Rebuild K0
« Reply #4 on: January 30, 2018, 05:42:38 PM »
That oxidation will buff right out!

The good news is that you have everything there. 


*except exhaust
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline MauiK3

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Re: CB750 Rebuild K0
« Reply #5 on: January 30, 2018, 07:34:14 PM »
What engine/frame number?
What a golden opportunity, making it as close to stock K0 as possible might be pricey but well worth it.
Do you know what color it was? Was it candy blue/green? My favorite.
If you go stock pipes make sure they are "no number" pipes, not 341's.
Lots of fun.
Steve
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline danyo

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Re: CB750 Rebuild K0
« Reply #6 on: January 30, 2018, 08:40:16 PM »
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Offline 77379

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Re: CB750 Rebuild K0
« Reply #7 on: January 31, 2018, 11:03:40 AM »
Hey Stev-o, Thanks, Unfortunately I think it’s going to take a little more than buffing to make it correct. 😩
Steve, I know it will be pricey - especially those correct pipes.💰
It still is wearing it’s original blue green, even has the original side covers with badges
E1011339 frame  1011541 (10/69)
I’ll post some more pictures when I get a little more into it.

Offline Johnie

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Re: CB750 Rebuild K0
« Reply #8 on: January 31, 2018, 01:42:13 PM »
Nice to see those early ones are still out there to be had. Looks like a nice project! Good luck and keep us informed of the progress.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline Stev-o

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Re: CB750 Rebuild K0
« Reply #9 on: January 31, 2018, 02:04:46 PM »
ok, 77279....James set the bar pretty high!   Good luck...
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline Johnie

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Re: CB750 Rebuild K0
« Reply #10 on: January 31, 2018, 02:37:55 PM »
Since James started it...here's my KO when I pushed it home back in 2007. A year later she looks like this...for sure worth the effort and money as far as I am concerned. It was my first KO project and the others that followed...well...I just could not help myself.
« Last Edit: January 31, 2018, 02:39:37 PM by Johnie »
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline 77379

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Re: CB750 Rebuild K0
« Reply #11 on: January 31, 2018, 05:35:09 PM »
You guys have all set the bar very high. I have seen those above pictures before and they helped motivate me to get this one started. I hope I can lean on you all for advice along the way. I started the tear down today and will continue tomorrow. Any suggestions on removing to side covers without breaking them. I pulled as hard as I thought I could without breaking them but they wouldn’t budge. Also, is there a good way to remove the data plate from the neck without tearing it up?
Gregg

Offline Johnie

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Re: CB750 Rebuild K0
« Reply #12 on: January 31, 2018, 06:18:05 PM »
Side covers...spray some lube on the tabs. Then I push on the tabs from the back and push them out. They break easy if you try to bend it by pulling them out. So the secret is to push on each tab from the back. You can also heat the rubber that the tabs slide into with a hair dryer. That should soften them up a bit too. The data plate...are you going to blast the frame? If not just cover it before it gets sprayed. If you are going to blast that frame you could try to grind down the top of the rivets and slide it off. Just need to be very careful like if you are using a Dremel.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline 754

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Re: CB750 Rebuild K0
« Reply #13 on: January 31, 2018, 07:16:44 PM »
You never pay too much, but sometimes you bought too early..
 But you get to enjoy and use it now.. nice early diecast, a 69 to boot.
Maker of the WELDLESS 750 Frame Kit
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My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

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Lost quite a few CB 750's along the way

Offline Terry in Australia

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Re: CB750 Rebuild K0
« Reply #14 on: January 31, 2018, 11:37:22 PM »
Nice! Looks like you need a few "unobtainium" K0 parts to make it original again, but as has been said, good (properly restored all original) K0 prices are going thru the roof, just be prepared for some frightening prices! ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

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Offline lash

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Re: CB750 Rebuild K0
« Reply #15 on: February 01, 2018, 03:01:32 AM »
My before and after.. 11/69
Analog mind in a digital world..

Offline lash

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Re: CB750 Rebuild K0
« Reply #16 on: February 01, 2018, 03:10:56 AM »
And its sister..
Analog mind in a digital world..

Offline SOHC4 Cafe Racer Fan

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Re: CB750 Rebuild K0
« Reply #17 on: February 01, 2018, 08:58:45 AM »
Those restored K0's are gorgeous.
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 JamesH

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Re: CB750 Rebuild K0
« Reply #18 on: February 01, 2018, 09:21:24 AM »
You guys have all set the bar very high. I have seen those above pictures before and they helped motivate me to get this one started. I hope I can lean on you all for advice along the way. I started the tear down today and will continue tomorrow. Any suggestions on removing to side covers without breaking them. I pulled as hard as I thought I could without breaking them but they wouldn’t budge. Also, is there a good way to remove the data plate from the neck without tearing it up?
Gregg
You'll be fine. Totally agree on the previous post re. side covers. Gently heat, always push from the back and then discard the old hard rubbers.

I personally leave the name plate riveted and mask very carefully (first with conventional masking tape (blue or green painters tape), then a second with duct/gorilla tape.

You can also gently lift the edges of the plate to ensure you get some paint coverage underneath the edges (to avoid an old/new witness line).

The VIN tags are both riveted and use an adhesive backing - difficult to remove without damaging the VIN tag.

Keep us posted on your progress...

James

Offline 77379

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Re: CB750 Rebuild K0
« Reply #19 on: February 01, 2018, 12:48:07 PM »
Johnie, I’m not married and don’t have enough hair for a hair dryer but that was the method of removing the side covers I was thinking of using with a little WD40. I was also planning to media blast the frame and thought I’d be better off removing the VIN tag with the dremmel grinder so it didn’t get wrecked during blasting, I may tape a thin gauge piece of metal over it and go easy on that area.
I agree, the after pictures of the above K0s are gorgeous. Mine is a long way from that at this point but that is the ultimate goal.
I know some of the parts I need will be tough to come by and come at a high price but I’m hoping it will be worth it in the end, at least to me anyway.
I’m not sure I bought it too early, I wish I bought it a while ago and was riding it today.
Actually, I’m glad I did get it when I did, the previous owner was going to use the motor for a go cart.
I’m going to try again to remove those side covers and some other parts tonight.

Offline Johnie

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Re: CB750 Rebuild K0
« Reply #20 on: February 01, 2018, 03:01:54 PM »
These KO's are becoming few and far between and you have to get them when you can find them. It would have been a shame for the PO to part it out. Did it come with a title?
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline 77379

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Re: CB750 Rebuild K0
« Reply #21 on: February 01, 2018, 03:13:17 PM »
No title but I have heard there is a way to get one from Vermont. I haven’t looked into that yet but I will. I had good and bad results with the side covers and air box. One side cover and the air box bottom had a previous cracks. One side cover had a broken mounting tab. I think I will need a new air filter also.

Offline Stev-o

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Re: CB750 Rebuild K0
« Reply #22 on: February 01, 2018, 03:43:47 PM »
No title but I have heard there is a way to get one from Vermont.

No way to get a title from them but you can get a registration. PM me for details when you are ready, better to not discuss it on a public forum.
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline 77379

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Re: CB750 Rebuild K0
« Reply #23 on: March 24, 2018, 01:03:26 PM »
I finally finished with most of the black paint work. I first bead blasted everything, then primed with PPG primer surfaced. A little bit of sanding on the pitted areas and then shot with a PPG 9300 Concept acrylic single stage urethane. I used a flattener on the paint to bring the gloss down about ten percent because that seems to be the original gloss on these frames in the visible areas. The pure acrylic urethane looked a little too glossy. I’m happy with the way it turned out. It seems like every project becomes two projects. I go to bead blast and the blaster needs to be fixed first, I go to paint and the gun is missing in action. Two steps forward and one step back but I’m making slow but steady progress.

Offline Sgt.Pinback

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Re: CB750 Rebuild K0
« Reply #24 on: March 24, 2018, 01:48:56 PM »
Good luck with the project!

Before and after KO pics
Doc, I love a motorcycle!

Offline 77379

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Re: CB750 Rebuild K0
« Reply #25 on: March 24, 2018, 02:57:43 PM »
Thanks for the encouragement. Your bike turned out fantastic. Do you have any idea roughly what VIN that duck tail seat changed to the flat back seat? Also, any idea when the wrinkle tank was no longer being used?

Offline Stev-o

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Re: CB750 Rebuild K0
« Reply #26 on: March 24, 2018, 03:50:21 PM »
Frame looks good, 77...
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline Sgt.Pinback

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Re: CB750 Rebuild K0
« Reply #27 on: March 24, 2018, 03:52:00 PM »
Ducktail seat for all K0, flat one came with K1.

Don’t know how long the wrinkle Tank came, but your early KO should have it.

Sorry to say but your bike misses some expensive K0 parts (double cut front fender, HM300 pipes, K0 seat , recessed ignition switch ...)
« Last Edit: March 24, 2018, 03:58:07 PM by Sgt.Pinback »
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Offline BPellerine

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Re: CB750 Rebuild K0
« Reply #28 on: March 24, 2018, 04:59:57 PM »
might still have the 2 hole rear fender though.
1978 CB 750K ard and webers
another anfob

Offline 77379

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Re: CB750 Rebuild K0
« Reply #29 on: March 25, 2018, 01:47:39 PM »
It was wishful thinking on the rear fender. A previous owner had put extra holes in it anyway to mount the rear turn lights so he could fit larger side bags. The guy I bought it from kept those for some reason. I realize there are a lot of expensive hard to find parts missing but that is the way it came. In a package I got two other K0 bikes both of them are missing the tanks and they are both later VINs. That is why I was wondering when they stopped using the wrinkle tanks. The tank that came with this bike is a repairable wrinkle tank fortunately.

Offline BPellerine

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Re: CB750 Rebuild K0
« Reply #30 on: March 25, 2018, 04:28:12 PM »
well you might have enough parts to build one nice one!
1978 CB 750K ard and webers
another anfob

Offline Don R

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Re: CB750 Rebuild K0
« Reply #31 on: March 25, 2018, 05:11:55 PM »
 Watch for the rolled rear rims. They are rounded on the bead area. No flat side at all really. Hard to find and expensive to buy. I rechromed the one on my sandcast. The Chrome guy said, you realize you can buy a rim for less. I said yes, but not this style rim. Good for him being up front about it. If you find two, call me lol. 
 
 You may find yourself looking at a lot of improperly listed parts on ebay. Knowledge is power in this case.
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Re: CB750 Rebuild K0
« Reply #32 on: March 25, 2018, 08:21:30 PM »
I finally finished with most of the black paint work. I first bead blasted everything, then primed with PPG primer surfaced. A little bit of sanding on the pitted areas and then shot with a PPG 9300 Concept acrylic single stage urethane. I used a flattener on the paint to bring the gloss down about ten percent because that seems to be the original gloss on these frames in the visible areas. The pure acrylic urethane looked a little too glossy. I’m happy with the way it turned out. It seems like every project becomes two projects. I go to bead blast and the blaster needs to be fixed first, I go to paint and the gun is missing in action. Two steps forward and one step back but I’m making slow but steady progress.

I'd like to raise a point here: in the 1970 frames Honda forgot for a while to include some drain holes in the lower frame. Since the K0-K2 frames (and even some K3) have an opening at the rear of the cradle where water can (and does) enter the lower frame, causing the frame to rot right at the back of the lower front engine bolsters, they were all supposed to get a 2.5mm (1/8" close enough) hole AFTER paint, just behind each bolster, on the bottom. We got a memo' from Honda about these in late 1971, asking the shops to check for, ostensibly, "painted shut holes in the lower frames". I have seen quite a few frames so adversely affected, and repaired a couple with new welding and new paint - all apart, of course.. :(
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Offline Terry in Australia

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Re: CB750 Rebuild K0
« Reply #33 on: March 26, 2018, 02:31:15 AM »
It was wishful thinking on the rear fender. A previous owner had put extra holes in it anyway to mount the rear turn lights so he could fit larger side bags. The guy I bought it from kept those for some reason. I realize there are a lot of expensive hard to find parts missing but that is the way it came. In a package I got two other K0 bikes both of them are missing the tanks and they are both later VINs. That is why I was wondering when they stopped using the wrinkle tanks. The tank that came with this bike is a repairable wrinkle tank fortunately.

Ha ha, I've got a K0 fender with holes in the same spot, except mine is painted white because it was a cop bike fender. I'm glad I'm not trying to restore a K0 now, those "unobtainium" parts are stupid prices. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline 77379

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Re: CB750 Rebuild K0
« Reply #34 on: March 26, 2018, 02:54:47 PM »
Instead of making one bike out of the three, if I can finish this one and if I have any money left I may take a stab at finishing the others. They are all missing the same expensive parts.
I’m not real clear on the rolled rims. All six rims appear to be egg shaped if I was to look at a cross section of it. I don’t see any flat part on the outside or inside. Maybe a picture of the two different rims would help identify them.
I didn’t notice any rot or even excessive rust anywhere when I bead blasted the frame. I even tapped around on it quite a bit listening for anything odd but all seemed to be ok. I like the idea of drilling the drain holes. I don’t plan on riding in the rain but it happens.

Offline Stev-o

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Re: CB750 Rebuild K0
« Reply #35 on: March 26, 2018, 02:58:11 PM »
I may have a front rolled rim that I dont plan to use.  Will have to check condition.
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........