Author Topic: 1976 CB750K Stock/Cafe Hybrid  (Read 34431 times)

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Offline heyjones

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1976 CB750K Stock/Cafe Hybrid
« on: January 14, 2010, 06:05:20 pm »
I'm getting ready to start tearing down my stock (for the most part) '76 750K. I wanted to post a kind of before and after, make a brief list of modifications that I'd like to make, and get some feedback/tips from you guys. What I want to end up with is a comfortable, dependable bike that I can take long trips on, and something I don't have to be polishing every weekend... something between stock and cafe. I kind of want to combine all the features that I like about the bikes I've seen in this forum, that kind of thing. So anyways, here's the shortlist of cosmetic changes that I want to make:

1) Paint: Strip and powder coat the frame, swing arm, etc. in black. Repaint the tank with the Garnet Brown color. It wasn't a color option in '76 but whatever. I'd like to keep the '76 decal, though. I also like the look of the black side covers. I'm on the fence about engine paint, maybe blacking out the non-aluminum parts of the engine and shining the rest. I saw a post where he used a sort of gun metal paint that I thought looked pretty slick, but I'm not sure how it would look with my color scheme.

2) Seat: I like the look of the rear end of the F models, and I'd paint it to match the tank. Does anyone know if a lot of modifications are necessary for swapping these seats?

3) Exhaust: I'm thinking about doing a 4 into 2, I like that symmetrical look, and wrapping the pipes. I've accepted the fact that I'm not going to keep this bike in pristine condition, so I don't want to be shining the exhaust all the time. And supposedly it cuts down on the heat and all that. Then go black or chrome on the muffler. Is there a huge performance difference between the 4-2 vs the 4-1 though?

4) Handlebars: I'd like to lower them a bit, but not too much as I'd like it to be comfortable on long rides. I've never tried the lower bars though, are they brutal? I want to mess with the gauge/dummy light setup too, maybe move the ignition switch and push button between the speedo/tach so I don't keep draining batteries. I'm also thinking about getting the older tach/spedo combo with the dummy lights in them so I don't have to mount them on the handlebar clamp where I can't see them and so I leave my blinker on for miles.

5) Headlight: I'm split between visor/no visor. I guess I can always get it and take it off if I don't like it.

And as far as the mechanical side of things:

6) Carbs: I think I'm going to leave the airbox alone, just clean them up and re-jet for the 4-2 pipes.

7) Engine: Complete tear down (my uncle builds hot rods, that should come in handy!). Fix whatever needs to be fixed. From what I gather doing a big bore on these isn't the best idea ever, but I'm not completely against it either. I'm not looking to do any racing or wheelies, but again, not completely against it!

8) Electronics: Completely re-wire the bike. I've already updated almost all of the electronics (rectifier, regulator, fusebox, Hondaman ignition)... I'm going to keep the points, though. I'm sure I'll have to get a little creative with the changes I want to make to the gauge cluster, but I'm thinking it should actually make things easier since I'm not routing all that stuff into the handlebars (at least on the right hand side). I saw a post on here with the cleanest headlight bucket ever, I'm sure I'll be bugging him about how he did that!

9) Rebuild the brake caliper, put some stainless steel hoses on... No dual disk or anything like that. And I'm going to keep the rear drum, just get everything cleaned up back there.

10) Oil Cooler: Pretty much just that, throw one on there.

I've attached a before/after Photoshop disaster... I'm working on a mockup for the handlebar configuration. Thanks in advance for any opinions you guys have, I've gotten so much inspiration (and so little sleep) from trolling through the other projects. Wish me luck!
1976 CB750K
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Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #1 on: January 14, 2010, 06:32:37 pm »
I found this post about swapping the K/F seats:

http://forums.sohc4.net/index.php?topic=15207.msg152966#msg152966

Basically the guy just recommends building a new seat pan to bolt the F seat to the K frame. Does anybody have any better ideas? I'm trying to find some detailed shots of how the seat hinge even works on the F models.
1976 CB750K
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Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #2 on: January 14, 2010, 06:50:38 pm »
Sorry, I'm using this thread to keep track of all my ideas. Here's some more research on the seat situation... I found a schematic for the K frame:



... and the F frame:



It looks like I'd need to grind off the seat hinges on the right hand side of the bike for starters. I'm still trying to figure out how the F hinge works, here's the schematic for the '76 model:



I wonder if another F model year would be a better fit, but I don't even know where to start with this one. I might be best off just picking one up and hack at it until I get it on there.
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Offline hahnda

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #3 on: January 14, 2010, 07:21:39 pm »
I have a 75K that someone put an F tank and seat on it. It looks ok but the way it was done the seat is not secure. The seat just lifts off the frame, no more hinges. It uses a pin to keep it from slipping. I could get some pics but like I said, it could be done better.
Kevin
CB750K4 in pieces
CB750K3 with F trim
CB750K7
CB500 Cafe Project
CB750 Cafe

Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #4 on: January 14, 2010, 07:30:40 pm »
Okay, so it has been done! I don't suppose you would know what year the '75F seat is, would you?
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Offline hahnda

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #5 on: January 14, 2010, 07:35:04 pm »
I do not know what year seat is on it but I can compare it to a 76F seat I have to see if it is the same?
Kevin
CB750K4 in pieces
CB750K3 with F trim
CB750K7
CB500 Cafe Project
CB750 Cafe

Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #6 on: January 14, 2010, 07:35:57 pm »
That'd be great, thanks!
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Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #7 on: January 18, 2010, 07:06:20 pm »
I ran into this today after letting the carbs soak... it looks like I'm missing a couple of jets. The first photo has two, the second is missing one on the left, and the third and fourth are missing one on the right. Any idea how this could have happened, or why?







« Last Edit: January 18, 2010, 07:08:35 pm by heyjones »
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Offline hahnda

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #8 on: January 18, 2010, 07:14:54 pm »
Your update reminds me I owe you some pics.
Kevin
CB750K4 in pieces
CB750K3 with F trim
CB750K7
CB500 Cafe Project
CB750 Cafe

Offline hahnda

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #9 on: January 20, 2010, 07:14:43 pm »
Ok here are some pics. Mods not done by me.







This bike was/is a K3. The seat is actually quite stable. With a little work and attention to detail it could look pretty decent I think.
Kevin
CB750K4 in pieces
CB750K3 with F trim
CB750K7
CB500 Cafe Project
CB750 Cafe

Offline Don R

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #10 on: January 20, 2010, 08:08:12 pm »
The jets are normal, those are the connecting (balance) tubes between the carbs and the end ones only have one jet each. The ones that look like they are missing are not drilled through. D.
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Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #11 on: January 21, 2010, 08:11:44 am »
Thanks for the pics, hahnda. So it looks like all you had to do was extend that rear mount on the frame and move the seat lock, is that accurate? And is that Gorilla Tape on the seat? I did the same thing about a year ago, but tried to match the seat pattern... first hot day though and I was glued to the bike! Thanks Don for the tip on the carbs, I'll stop freaking out now.
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Offline hahnda

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #12 on: January 21, 2010, 08:16:43 am »
There is also a hole drilled in the frame brace and a pin welded to the seat. Might be hard to see that pin in my picture.

Yes that is tape. This bike needs a lot of love.
Kevin
CB750K4 in pieces
CB750K3 with F trim
CB750K7
CB500 Cafe Project
CB750 Cafe

Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #13 on: February 11, 2010, 10:43:17 pm »
Well here's where it's at now. I picked up a hydraulic lift to remove the front end, which was really difficult to use since the kickstand mount was in the way. Next step is to remove the engine from the frame and start replacing gaskets, check the cylinders, etc.
1976 CB750K
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Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #14 on: February 13, 2010, 02:50:57 pm »
It's been pretty slow going the last couple of weeks between work and weather, but today I managed to drain the oil and pull the engine out of the frame. I laid the whole thing on its side as I've seen suggested on here and it worked out great. I think I had drained the oil in the wrong order or something since as soon as I turned it over, oil came pouring out all over the place. Should have read up on that! I think you drain the oil tank first, then the bottom end. Also, because of the lift I was using I wasn't able to remove the oil filter until I had it on its side, which also dumped oil all over the place. Awesome.

So now I'm on to cleaning. I'm sending the swing arm off to HondaMan to have the bushings rebuilt, and once I get that back I'll take the frame, mounts, stands, etc. in to be powder coated. I'm still on the fence about the color scheme for the engine, though I'm leaning towards keeping the case the same color and paining the fins black.
1976 CB750K
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traveler

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #15 on: February 14, 2010, 09:58:12 am »
Get some thin "Mechanix" gloves...it'll save your hands with all the cleaning and scrubbing.

You just have to get things down to where you want them to look.

Looks like a good project...have fun!

~Joe

Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #16 on: February 23, 2010, 06:07:54 pm »
I've got the frame, swing arm, stands, etc. sent out for powder coating. They should be done by the weekend. Found a guy through craigslist that could get everything done, with no prep by me, for $300. Here's hoping it isn't too good to be true! I'll post photos when I get everything back, along with his contact info. Just ordered a (hopefully) complete engine gasket kit from PartsNMore. The brand is Athena. Here are the links:

http://www.partsnmore.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=1&Product_Code=18-0110

http://www.partsnmore.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=1&Product_Code=01-9018

From what I've read here I'll want to order a set of the "pucks" from Honda, are there any other gaskets I should watch for? I'm hoping I won't have to get too far down into the bottom end of the engine, since aside from the cylinder gaskets nothing else seems to be leaking.

I'm stripping the paint off of the brake calipers now using aircraft stripper. The auto store near me had it in a spray can, I figured I'd give that a shot. I'll post photos of that as well. The piston I pulled out looked fine, no pitting or anything. I'll just hit it with some steel wool and replace the gasket in there. I also want to pick up one of these Speed Bleeders:

http://speedbleeder.zoovy.com/

Debating on what to do about the brake lines as far as using the steel braided line, etc. I would ask for "any suggestions", but I know there's a ton of posts on that topic already.
1976 CB750K
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Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #17 on: February 23, 2010, 06:52:24 pm »
Also, this is something I've been thinking about doing with the tank. I haven't seen many bikes on here with rubber knee pads on it, maybe there's a reason for that... ?
1976 CB750K
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Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #18 on: March 05, 2010, 11:30:47 am »
I found a great project blog:

http://www.thesandmann.com/motorcycles/cafe-racer-project

Between that, this forum, 5 different manuals and HondaMan's new book I should be covered!
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Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #19 on: March 07, 2010, 10:17:33 am »
So I'm staring to tear down the engine, and I'm noticing a lot of small cracks on the outside of the bottom end of the casing. The photo I attached is above the right hand side of the engine, with the paint stripped. Should I be concerned about this?
1976 CB750K
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Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #20 on: March 07, 2010, 10:43:52 am »
After some searching I think I've learned that it could just be cold-cast lines, which "can happen during the casting process with aluminum". Here are the threads on it:

http://forums.sohc4.net/index.php?topic=32467.0

http://forums.sohc4.net/index.php?topic=31143.0

So I should be alright. I'll try to sand them down as much as I can but the general consensus seems to be that the only way to really get rid of it is to paint over them.
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Offline rickmoore24

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #21 on: March 07, 2010, 11:31:21 am »
Awesome! Yes, please paint that motor. I skipped that step and I'm regretting it a little bit more and more each day.
1972 CB750 K2 (Daily Runner)
1972 CB750 K2 (Sold)
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Offline michelangelo

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #22 on: April 20, 2010, 06:20:49 pm »
Keep us updated...  :)
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Offline smack

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #23 on: April 20, 2010, 06:50:38 pm »
check these guys out for tankpads:

http://www.techspec-usa.com/

They can make you custom pads from your drawings.. I sent them a .pdf
super nice guys to. I got both sides and a top pad for $50.

Offline heyjones

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Re: 1976 CB750K Stock/Cafe Hybrid
« Reply #24 on: April 20, 2010, 06:53:04 pm »
Those look awesome! Thanks for the heads up. I'll be posting some progress photos tonight, it's been pretty slow but I'm putting things together as I get to them. I have yet to crack the engine open...
1976 CB750K
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