Author Topic: 1978 CB750K Project.  (Read 4260 times)

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Offline RainCityRider

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1978 CB750K Project.
« on: August 16, 2017, 12:18:04 AM »
I have been hoarding 1978 parts for a while mostly to keep my stock bikes in good nic. I have 2 runners and 1.75 parts bikes plus many extra bits. Time to clean house and make the 1.75 parts bikes into one.

The plan is to do a frame off retro mod scrambler build. I have started acquiring parts for this. Many of which I have gotten from Cognito Moto, Thanks Devin! And now will start mocking up the bike and making mistakes..... I mean decisions on what to do and how to do it. I will have many questions and I hope when I'm done I will have helped answer some of yours.

Oh, and I will have a sick bike!!!!!

- Step one clean'ish and organize the garage.
78 CB750K
78 CB750K
78 CB750K
99 ZRX 1100

Offline RainCityRider

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1978 CB750K Project.
« Reply #1 on: August 16, 2017, 08:02:04 PM »
Got the fork installed, shocks on, and tires mounted. So I Started some mock up to inspire myself.

Wheels are look'n good with some rubber on them! Devin at Cognito Moto did a great job on the laces! I need to find an anodizer here in Seattle to match the thing the rear sprocket mounts on to the hub. Anyone have a good person in PNW?


Waiting for front rotors and a few other bits to come in so I can really get an idea of what she will look like.
I hope to get some real work done on Monday after the eclipse.


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78 CB750K
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Offline SOHC4 Cafe Racer Fan

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Re: 1978 CB750K Project.
« Reply #2 on: August 16, 2017, 09:42:00 PM »
Ask Isaac Seigl at Speedy Seigl
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 RainCityRider

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Re: 1978 CB750K Project.
« Reply #3 on: August 17, 2017, 09:11:12 AM »
Ask Isaac Seigl at Speedy Seigl
I contacted him. Thanks!


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78 CB750K
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Offline RainCityRider

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Re: 1978 CB750K Project.
« Reply #4 on: August 21, 2017, 03:02:02 PM »
Ask Isaac Seigl at Speedy Seigl
I contacted him. Thanks!

He says that anodizing cast parts is not advisable. Says they have to many impurities.


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Offline SKTP

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Re: 1978 CB750K Project.
« Reply #5 on: August 22, 2017, 10:42:12 AM »
Wheel look amazing...what front-end is that?
1978k rebuild thread http://forums.sohc4.net/index.php?topic=68423.0
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Offline RainCityRider

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Re: 1978 CB750K Project.
« Reply #6 on: August 22, 2017, 01:42:33 PM »
Wheel look amazing...what front-end is that?
The front end is a GSXR conversion from Cognitomoto.


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Re: 1978 CB750K Project.
« Reply #7 on: August 22, 2017, 01:45:10 PM »
Anyone know where I can get rear wheel spacers! Thought the rear wheel from Cognitomoto was plug and play. Need about 15mm on top of stock.



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Re: 1978 CB750K Project.
« Reply #8 on: August 22, 2017, 01:45:36 PM »
Maybe I should buy a lathe!


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Offline SKTP

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Re: 1978 CB750K Project.
« Reply #9 on: August 22, 2017, 02:49:59 PM »
I have always been under the impression that using GSXR front fork lowers the bike's front end. Is this correct?
1978k rebuild thread http://forums.sohc4.net/index.php?topic=68423.0
BIKE OF THE MONTH - OCTOBER 2017
2003 Ducati M800ie
1997 Honda CR-V
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1966 Honda S90

Offline RainCityRider

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Re: 1978 CB750K Project.
« Reply #10 on: August 22, 2017, 04:10:22 PM »
Not sure. Haven't really had it on the ground yet. Devin at CognitoMoto would know I'm sure. He made the kit.
78 CB750K
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Offline SKTP

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Re: 1978 CB750K Project.
« Reply #11 on: August 22, 2017, 05:48:40 PM »
do you have the original forks still? Are they longer? I ask because I have considered the swap for a very long time. I think I would have to sacrifice the Lesters....
1978k rebuild thread http://forums.sohc4.net/index.php?topic=68423.0
BIKE OF THE MONTH - OCTOBER 2017
2003 Ducati M800ie
1997 Honda CR-V
2004 Honda CR-V
1966 Honda S90

Offline calj737

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Re: 1978 CB750K Project.
« Reply #12 on: August 22, 2017, 06:19:50 PM »
Maybe I should buy a lathe!

Easiest thing to do it buy a small piece of aluminum tubing with the correct ID, and cut it to length. It doesn't need to be turned especially. But, if you want it done so it looks "high end", send me the exact measurements via PM and I'll turn one up for you this weekend and post it off to you Monday or Tuesday. Should take me all of 30 minutes.Then you can drop it off to be anodized with your other stuff-
'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 calj737

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Re: 1978 CB750K Project.
« Reply #13 on: August 22, 2017, 06:21:15 PM »
I have always been under the impression that using GSXR front fork lowers the bike's front end. Is this correct?
No, not really. What does occur often is the wheel is changed to an 18 or 17 which does lower the front. The GSXR uses a different offset than the stock bike, so that effects the rake, but not the length really.
'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

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Re: 1978 CB750K Project.
« Reply #14 on: August 22, 2017, 07:30:40 PM »
I have always been under the impression that using GSXR front fork lowers the bike's front end. Is this correct?
The GSXR uses a different offset than the stock bike, so that effects the rake, but not the length really.

Yes, and this is the reason why (if you consider doing such a conversion) to invest in a triple tree with additional offset (such a Cognitomoto) to restore some or all of that offset.
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 RainCityRider

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Re: 1978 CB750K Project.
« Reply #15 on: August 23, 2017, 10:14:14 PM »
I will let you know If I need help. Devin is working on helping me sort it. I could be missing something.
78 CB750K
78 CB750K
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Offline RainCityRider

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Re: 1978 CB750K Project.
« Reply #16 on: August 24, 2017, 07:48:19 PM »
I have always been under the impression that using GSXR front fork lowers the bike's front end. Is this correct?
The GSXR uses a different offset than the stock bike, so that effects the rake, but not the length really.

Yes, and this is the reason why (if you consider doing such a conversion) to invest in a triple tree with additional offset (such a Cognitomoto) to restore some or all of that offset.
Exactly why I did buy mine from cognito


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78 CB750K
78 CB750K
78 CB750K
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Re: 1978 CB750K Project.
« Reply #17 on: August 24, 2017, 08:45:22 PM »
I have always been under the impression that using GSXR front fork lowers the bike's front end. Is this correct?
The GSXR uses a different offset than the stock bike, so that effects the rake, but not the length really.

Yes, and this is the reason why (if you consider doing such a conversion) to invest in a triple tree with additional offset (such a Cognitomoto) to restore some or all of that offset.
Exactly why I did buy mine from cognito


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Smart choice.
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 RainCityRider

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Re: 1978 CB750K Project.
« Reply #18 on: August 25, 2017, 02:18:12 PM »
Devin and I sorted it out. But I might need a billet spacer so I can get it anodized.

Does anyone make an aftermarket cush drive made out of billet? I would love to be able to anodize that too. Issac at Speedy Siegl said cast alloy doesn't anodize well.
78 CB750K
78 CB750K
78 CB750K
99 ZRX 1100

Offline SOHC4 Cafe Racer Fan

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Re: 1978 CB750K Project.
« Reply #19 on: August 25, 2017, 05:23:38 PM »
Devin and I sorted it out. But I might need a billet spacer so I can get it anodized.

Does anyone make an aftermarket cush drive made out of billet? I would love to be able to anodize that too. Issac at Speedy Siegl said cast alloy doesn't anodize well.

Not presently available.  I suppose you could find someone to scan a stock piece and CNC it out of billet.  Or just powder coat it.
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 RainCityRider

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1978 CB750K Project.
« Reply #20 on: September 06, 2017, 06:46:17 PM »
Devin and I sorted it out. But I might need a billet spacer so I can get it anodized.

Does anyone make an aftermarket cush drive made out of billet? I would love to be able to anodize that too. Issac at Speedy Siegl said cast alloy doesn't anodize well.

Not presently available.  I suppose you could find someone to scan a stock piece and CNC it out of billet.  Or just powder coat it.
I don't think powder coat would look great next to anodized. Maybe Cognito will bake a billet one


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78 CB750K
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Offline calj737

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Re: 1978 CB750K Project.
« Reply #21 on: September 06, 2017, 06:49:26 PM »
I think the powder coat can look just fine next to the anodized, depending upon the finish you choose for the powder. There's heaps of "blacks" out there, and one should be close enough to the anodizing to not be an eyesore. Also, Cognito does a variety of blacks in their anodizing, so you can always get a match. Worst case, strip the anodizing and coat both pieces!
'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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Re: 1978 CB750K Project.
« Reply #22 on: September 06, 2017, 09:29:39 PM »
I think the powder coat can look just fine next to the anodized, depending upon the finish you choose for the powder. There's heaps of "blacks" out there, and one should be close enough to the anodizing to not be an eyesore. Also, Cognito does a variety of blacks in their anodizing, so you can always get a match. Worst case, strip the anodizing and coat both pieces!

Agreed.  Try a deep dark matte black pc.
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 RainCityRider

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Re: 1978 CB750K Project.
« Reply #23 on: September 07, 2017, 08:17:02 AM »
I think the powder coat can look just fine next to the anodized, depending upon the finish you choose for the powder. There's heaps of "blacks" out there, and one should be close enough to the anodizing to not be an eyesore. Also, Cognito does a variety of blacks in their anodizing, so you can always get a match. Worst case, strip the anodizing and coat both pieces!
I will look into it.


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78 CB750K
78 CB750K
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99 ZRX 1100

Offline RainCityRider

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Re: 1978 CB750K Project.
« Reply #24 on: October 28, 2019, 12:56:50 PM »
What should I do to prevent corrosion during mock up after cutting side cover tabs and other extraneous bits off?

Any type of spray paint or something recommended?
78 CB750K
78 CB750K
78 CB750K
99 ZRX 1100