CB750K Builds

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Re: 1980 CB750K Build

TOOLS1
Administrator
Oh, the Buffet Racer.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: 1980 CB750K Build

StealthCB
I like it, man!

Well, I picked up another bike today! This time it's a 1973 CB750! The guy thought it was a 1974 then we pulled it out and he then thought it was a 1972. However, the 22xxxx vin says it's a 1973. It was manufactured on 9/72. Doesn't have the original style seat, which I really wanted, and it's missing the front brake caliper. Can someone tell me what year CB750 this seat belongs too? Also, if I used a set of dohc cb750 forks, could I still use the K3 wheel? I ask because the brakes are better and cheaper and would be a decent upgrade, instead of buying a GL1000 front end or just buying the K3 brake caliper and mounting bracket. Thanks guys!

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Re: 1980 CB750K Build

TOOLS1
Administrator
I have no idea of what that seat came off of. As for the front end, the DOHC K model single disc is way better than the SOHC disc. One option is to install another disc and caliper onto your front end and make it a dual disc. I have done that to several CB 750s and you can lock up the front wheel. Just check out the duel disc on the Buffet Racer.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: 1980 CB750K Build

shinyribs
Administrator
I agree with Tools. I'd use the DOHC brake if at all possible. The SOHC brakes are...ok...and if you double them up they are pretty decent, but the rotor material itself is very hard and the bastards squeal horribly.

If you do go with SOHC brakes I can loan you a drill pattern to make them purdy. They drill really easy. Same pattern also work on SOHC F model rear discs.




IIRC, a DOHC front end simply bolts on to a SOHC. Tools,is this right?
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Re: 1980 CB750K Build

StealthCB
Thanks for the advice, guys! The brake caliper and mounting bracket is not that easy to find and for a decent price, that's why I think it would be great to just go the DOHC front end route. They  are both 35mm forks and should bolt right up from what I've read. I am going to check some thing today when I'm at the shop.
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Re: 1980 CB750K Build

TOOLS1
Administrator
In reply to this post by shinyribs
"IIRC, a DOHC front end simply bolts on to a SOHC. Tools,is this right? "
Yes, it is a bolt on swap.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: 1980 CB750K Build

StealthCB
So... I bought another bike, this time it's a proper SOHC CB750! Check out the new video to see more! I'm pretty excited about this bike!!

https://youtu.be/o90FcKqYVMo
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Re: 1980 CB750K Build

shinyribs
Administrator
SOHC!!!

I really like the DOHC bikes. And if I'm honest, they are better bikes. Better handling, better brakes, better power ( down low), smoother gearbox...I like them. But...I LOVE the SOHC bikes more.

Those cracked cases around the ignition suck, but it's superficial. Don't sweat it too much. Worse case scenario = you epoxy it together and it looks a little weird.

Speaking of looking weird, what size is that rear tire? My eyes might be lying, but it looks like a drop center  Harley rim (16"). Pretty common thing to see on these bikes for some reason.

Now...stop taking bikes apart until you have one running.You'll end up with boxes full of bike parts and no bikes before you know it lol.

vintgecb750.com sells a new wiring harness for about $75. That might seem expensive, but it'll be a huge peace of mind/ time saver/ increase in reliability to just slap a fresh harness on there and rock on.
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Re: 1980 CB750K Build

StealthCB
Hahaha!!! Ok, ok, I will focus in on what I have. I believe I will probably get the 1973 up and running properly before the dohc, as I am not planning to completely strip the engine. I'm going to leave it in the frame and just get the bike hopefully going strong again. Ready to clean the carbs up some. Now, pods are much easier to tune on these, correct?

Also, I have no idea about the rim, but I will look. I found a new wiring harness for $64 at one of the stores online, so I may buy that eventually. I'm going to see about salvaging mine first. I have an extra wiring harness in decent shape, but it doesn't look to be the same year, as it's missing some things.
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Re: 1980 CB750K Build

TOOLS1
Administrator
After watching you wrestle that DOHC engine out of the frame, which is one of the easiest engines to remove/replace, I am glad you are not going to try to remove the SOHC engine, which is a hard one to remove/replace.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: 1980 CB750K Build

StealthCB
Hahaha!!! Well, it may happen a long time down the road, but I am definitely not tackling that anytime soon! My priority is simply getting the engine running first then going from there. Also, I didn't research enough about how exactly to remove the dohc engine, so I just kind of went after it.
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Re: 1980 CB750K Build

shinyribs
Administrator
Just a heads up in case you DO get a wild hair and decide to pull the SOHC. Don't even attempt to lift the engine out of the frame. Drain the engine, strip off the forks and rear wheel, lay the bike on it's side, unbolt the engine, lift the frame off the engine.

Any other way will make you hate life
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Re: 1980 CB750K Build

TOOLS1
Administrator
In reply to this post by StealthCB
" I just kind of went after it. "
So that is what you call that.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: 1980 CB750K Build

StealthCB
In reply to this post by shinyribs
Great advice, thank you! However, I am leaving it in for as long as I can.

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Re: 1980 CB750K Build

shinyribs
Administrator
In reply to this post by TOOLS1
TOOLS1 wrote
" I just kind of went after it. "
So that is what you call that.
TOOLS

Must a Virginia boy thing? Getting after it is when you know things are getting serious. The talk is over, it's time to get the job done.
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Re: 1980 CB750K Build

StealthCB
Haha!! Maybe it is! I am definitely a Virginia boy!

Ok, I need some input and advice from the masters.

If you were me, would you buy new fork tubes, rebuild the oem forks, buy a brake caliper and mount, or would you use a pair of DOHC forks, rebuild them and use the disc brake setup from that?

Update: I cleaned up my gauges a bit, so they are at least presentable, cleaned up the stock wiring harness some and am still debating just going ahead and buying a new one, and I am about to take apart and clean my carbs! Progress is being made, just more slowly than I would like.
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Re: 1980 CB750K Build

TOOLS1
Administrator
Since you have the complete DOHC forks, I would say put new seals and oil in them and use them.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: 1980 CB750K Build

StealthCB
That's what I'm leaning towards. Also, do you all have good luck with stock bore size master cylinders, or is a good 12mm master cylinder the golden ticket?
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Re: 1980 CB750K Build

TOOLS1
Administrator
I have never had any problem with a stock master cylinder. However, I think they are larger than 12mm.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: 1980 CB750K Build

StealthCB
Ok. Yes, I believe the stock one is 14mm.

If you haven't seen this diagram, take a look in this article. It's really intriguing.

http://www.vintagebrake.com/mastercylinder.htm
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