Author Topic: Edgar's 1977 750K  (Read 3083 times)

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Offline Edgar

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Edgar's 1977 750K
« on: May 10, 2016, 08:34:54 AM »
Hello all, my names Edgar and I picked up a non running 77 750k back in March and I'm ready to make some progress on it. I owned a suzuki savage (or LS650) about 5 years ago and that was my last true motorcycle. Currently I ride around town on a glorious and quite manly Honda Ruckus haha.

But anyway, this is my new member thread so you can view some pics:
http://forums.sohc4.net/index.php/topic,156373.0.html

So I'm starting this thread to ask questions because the search function on here isn't as precise as other forums i frequent.

The goal with this bike is somewhere in between stock and brat. I want to keep it as stock as possible, I guess the only difference will be no front fender, bobbed rear fender, different bars, and a different seat. I will not chop the stock fenders however, I promise they will not be sacrificed.

So I've ordered everything I think I need to rebuild the carbs, new stock airbox is on its way, new carb to airbox boots, carb to engine rubber boots are soaking to get softened back up, and a battery. Previous owner said that's all it should need to run, we'll see how that goes.

My first two questions so I can get an idea in my head of how this will look once finished are:

The brat style seat, is it necessary to chop the frame in order to mount a seat like that? Because I don't want chop any of this all original bike. I don't want to do anything that isn't reversible because I do respect that it is a classic

Second, would it be sac relig to put a PRE 1977 tank on it?? I really love the look of the gas cap on top of the tank, originally I wanted a 75 550 but I couldn't pass up this deal.

Thanks to anyone who read all this, and I look forward to your responses/suggestions!


Offline SOHC4 Cafe Racer Fan

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Re: Edgar's 1977 750K
« Reply #1 on: May 10, 2016, 09:42:42 AM »
Edgar,

Welcome.  That's a decent looking K7 you have.  It's difficult to tell, but appears that you have some weeping in your head and possibly your base gaskets.  If the leak is not too significant you may want to hold off on pulling the motor and just keep an eye on the leak and your oil level.

There are many folks who are not huge fans of the brat-style seat.  I was once smitten but passed.  They are not very comfortable for any appreciable distance or time in the saddle, but it's your bike and your choice.  If you go this route, make sure your seat has adequate padding.  To fit one, however, you will need to cut out the crossmember that also serves as the mount for your inner and outer rear fenders.  You will need to replace this cross-member (to maintain structural integrity and prevent frame twist) by welding in either (1) a new cross-member flush with the frame rails or (2) as frame hoop.  Note: depending on where you mount your frame hoop, you could run into clearance issues with the rear tire. 

Yes, you CAN fit a pre-1977 gas tank on the K7 frame.  However, the lengths of the gas tanks vary.  This will affect the gap/fitment of the seat.  You can preserve the stock seat and even the hinges, simply by re-mounting the matching hinges on the seat.  Here are some photos of my K7 with different tank/seat configurations as it evolved:

Ver 1.0


Ver 2.0 (re-worked seat)


Ver 3.0 (earlier 750K tank)


Ver 4.0 (reworked seat and tank)


Ver 5.0 (slightly reworked seat and NEW 750F tank)


Ver 6.0 (new seat with F tank) CURRENT
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 Edgar

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Re: Edgar's 1977 750K
« Reply #2 on: May 10, 2016, 11:14:26 AM »
Edgar,

Welcome.  That's a decent looking K7 you have.  It's difficult to tell, but appears that you have some weeping in your head and possibly your base gaskets.  If the leak is not too significant you may want to hold off on pulling the motor and just keep an eye on the leak and your oil level.

There are many folks who are not huge fans of the brat-style seat.  I was once smitten but passed.  They are not very comfortable for any appreciable distance or time in the saddle, but it's your bike and your choice.  If you go this route, make sure your seat has adequate padding.  To fit one, however, you will need to cut out the crossmember that also serves as the mount for your inner and outer rear fenders.  You will need to replace this cross-member (to maintain structural integrity and prevent frame twist) by welding in either (1) a new cross-member flush with the frame rails or (2) as frame hoop.  Note: depending on where you mount your frame hoop, you could run into clearance issues with the rear tire. 

Yes, you CAN fit a pre-1977 gas tank on the K7 frame.  However, the lengths of the gas tanks vary.  This will affect the gap/fitment of the seat.  You can preserve the stock seat and even the hinges, simply by re-mounting the matching hinges on the seat.  Here are some photos of my K7 with different tank/seat configurations as it evolved:

Ver 1.0


Ver 2.0 (re-worked seat)


Ver 3.0 (earlier 750K tank)


Ver 4.0 (reworked seat and tank)


Ver 5.0 (slightly reworked seat and NEW 750F tank)


Ver 6.0 (new seat with F tank) CURRENT


Thanks for the info. Hmmm, I don't want to cut the frame so maybe I'll just get the stock seat reworked. Im just not a fan of the high look of the seat, so maybe just get of the foam taken off and get some gel padding in there. I'm a long ways from that anyway so I have plenty of time to think about it.

It definitely does have a leak somewhere in the head. At least I think it does, theres also some leaking at the headers. My goal is to get this running, after that I have a trusty well known mechanic in my area that will dig into the more complex things like the engine. I'm very limited in knowledge and skill so I'll do what I can, and after that I'll pass it to him. He's also going to powder coat the frame (black) and paint my tank/side covers.

CB750 cafe racer fan, it looks to me like you did chop the frame on your different builds right?

Offline SOHC4 Cafe Racer Fan

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Re: Edgar's 1977 750K
« Reply #3 on: May 10, 2016, 03:05:14 PM »
"Chop" is probably an overstatement.  The frame has the following modifications:

(1) the seat still retains the main raised cross-member but the ends of the tail of the frame rails have been cut and plugged.
(2) I have installed a Gordon's frame kit.  This is a robust, over-engineered kit that allows you to unbolt and re-bolt the top frame rails so that you can service the engine without removing it from the frame, and makes removing and installing the engine MUCH easier.  Some purists do not condone this modification as devaluing the frame, but if you are not doing an exacting restoration it is an excellent, practical modification and it does not sacrifice the structural integrity of the frame. In addition to the Gordon's kit, Frank aka 754 makes a weld-less kit that does the same thing. 
NOTE: In the absence of a frame kit, you cannot remove the valve cover or disassemble the top end of the engine without removing the engine.  There is just no physical way to do it.
(3) Seat mounting tabs have been welded to the top frame rails.
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 Edgar

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Re: Edgar's 1977 750K
« Reply #4 on: May 10, 2016, 06:20:14 PM »
Ok, you've definitely got my mind running with new ideas. To chop or not to chop?

But for now, I have a dilemma, while dunking one of the carbs into cleaning solution my clumsy ass lost the brass washer that goes at the end of this needle. I can't seem to find just the washers being sold without purchasing the whole needle, which if you look at the pic I think I can reuse These needles after I clean them up. Any input guys?


Offline Edgar

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Re: Edgar's 1977 750K
« Reply #5 on: May 17, 2016, 08:23:06 PM »
Does anyone have a link to a good carb rebuild thread for the PD 77 carbs? All the stuff I've clicked through after a search has old broken links and missing pictures. Appreciate it if anyone does

Offline Edgar

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Re: Edgar's 1977 750K
« Reply #6 on: May 24, 2016, 09:23:22 AM »
Hey guys, how soft are the manifold to carb boots supposed to be? I've had them in a oil of wintergreen/alcohol solution for a week and only the ends are squeezable, the main body is definitely softer than before but no where near as soft as the ends. Is it supposed to be as soft as the carb to airbox boots?

Offline SOHC4 Cafe Racer Fan

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Re: Edgar's 1977 750K
« Reply #7 on: May 24, 2016, 09:57:11 AM »
You might want to reach out by PM to flybox1 regarding your carb issues.
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 flybox1

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Re: Edgar's 1977 750K
« Reply #8 on: May 24, 2016, 10:45:53 AM »
Hey edgar....thanks for reaching out.   is a needle washer all you need?
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline SOHC4 Cafe Racer Fan

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Re: Edgar's 1977 750K
« Reply #9 on: May 24, 2016, 02:18:24 PM »
I love it when a plan comes together.

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 Edgar

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Re: Edgar's 1977 750K
« Reply #10 on: May 24, 2016, 07:35:50 PM »
Hey edgar....thanks for reaching out.   is a needle washer all you need?

I think I'm gonna need all four o rings and washers for the screw set. I think that's what it's called, that's what partzilla lists it as. If you see my pic above of those screws, do you think they're reusable?

And thanks cafe racer fan ;)

Offline Edgar

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Re: Edgar's 1977 750K
« Reply #11 on: May 29, 2016, 05:30:08 PM »
Flybox1 do you have those parts?