Topic: 1977 CB750K Cafe/Rod Build - Update 10-3-11

[Johnny5]

Well, I began my winter build and I'll keep updating this thread as I move along.

Here she is the day after bringing her home. Bike only has 14,000 miles and runs strong. I went through and adjusted the valves, timing, cam chain, cleaned the carbs, then sync'd them up. Most of the work is going to be cosmetic.



I added pods and rejetted. Bike runs perfect.



I found a tank online and it was nasty looking but salvageable. So I gave it an electric bath to remove the rust and filled in some dents and sanded it down. See the progression below:









Tank is primed and ready for paint.

[Johnny5]

Got the clubman handlebar installed.




Then last week, I decided I wanted knee dents. I cut out my pattern and traced it on the tank.



I took a deep breath, squeezed my rubber mallet and gave it a whack.



This is where the tank is tonight. I still have to sand a little more, but it's really close and Im happy with the results.




I began dismantling the bike. Got the rear fender/lights off and the seat too. I think this bike is gonna look really nice.






That's all for now. Thanks for reading.

[BlindJoe]

Looking good man.

[wannabridin]

wow, that IS clean!  now all you need to do is get some new fork legs, or at least clean that rust up...  do you have any pictures of your knee dent progression?  what tools you used?  those look great, i would love to do some of those when i start tearing mine down!! 

one other thing, what method of electrolysis did you use to get rid of the rust?  washing soda with a piece of steel rod as an electrode?  thanks a bunch, looks great!

[Johnny5]

For the knee dents, I just cut out my pattern, traced it on the tank, and used a rubber mallet and worked my way from the middle of the pattern to the outside of the pattern. I was surprised how easy it was to form this. The hard part is getting it smooth with the body filler. But I blobbed and formed it the best I could around the whole knee dent area. Then, after about 3 hours of sanding, you see the end result. Im going to smooth it out a little more and call it good.

The electroylsis method I used was baking soda. I know someone swears by only using washing soda, but baking soda worked well for me. About a cup of soda to the tub of water. I put the negative to the tank, and the positive to a coat hanger rod dipped into the water.

I have some fork legs on order as I type this. I'll be ditching the stock headlight mounts and using either the older style fork boots or something. Havent really decided yet.
 

[Joel]

The first thing I thought when I saw this was APPLE! 

Now that I look again, it screams RADISH too.

[Johnny5]

[Otto]

What is the power source for the bath? Not 110V is it?

Bob

[Johnny5]

What is the power source for the bath? Not 110V is it?

Bob

I used a battery charger set at 12v  2amp. Took a couple of days to complete.

[Johnny5]

Looks clean.

Im curious why my forks always look longer than other bikes, where the fork boots would be?

[SOHC4 Cafe Racer Fan]

Your forks DO appear longer.  I'm not sure if it's an optical illusion because you are missing the HONDA fork brace.

[Otto]

Where'd you get that seat?

Bob

[Johnny5]

Johnny5,
Brilliant looking tank!  How did you keep the knee dents symetrical from left to right as to depth?

Thanks man, appreciate it. I completed it really just by touch and eyeballing it and a lot of patience. The only measurements I did were to keep the size (diameter and placement) of the knee dents.

[Johnny5]

I try to do something small each day. Today, I took apart the rear fender and taillight assembly. I want chrome front and rear fenders on the bike, so Im going to trim/crop the fender where it mounts to the frame, that I can keep the smooth edges along the fender.

Fender shines nice.

[KB02]

Im curious why my forks always look longer than other bikes, where the fork boots would be?

Yeah, now that you mention in, your front end does look a little different. Maybe a PO put longer forks on it? What size is your front tire (550 front end?)

Well, about mid next week you can check the length against some other K8 forks. 

[Johnny5]

This will be interesting to find out when the forks tube arrive.

[Johnny5]

Today, I took off the pipes and began cleaning them up. Surprisingly, it's mostly surface rust. I have them in an electric bath along with a few other rusty parts. We'll see how they look in a day or so. After that, I tore down the front end, removing the forks, front fender and brake assembly. Will begin cleaning the brake caliper also. Im going to work on modifying the headlight mount ears and Ive got an idea that I haven't seen yet for the fork boots that I think is going to look really nice.

Pretty soon, the engine will be coming out.


Here's what the fender is going to look like mounted.

[Johnny5]

Got a pair of original shocks on the bike now, and yes, the PO must have put 4" longer fork tubes since these are shorter.


No wonder why my centerstand wouldnt lift the rear tire off the ground....   After installing the standard size forks, the rear tire lifts up about a 1/2". I like when things work normally.

No it's time to pull the motor. It's getting really cold here in Michigan and I gotta get this stuff done and done into the warm basement.

[duganc1717]

Flashback to my K7!!

Carpy is doing some mods (clubmans, fender, lights, seat, shocks, exhaust with tank in progress) on it. 

Here's what it looked like before . . .


Here's what it looks like now. . .



And what it sounds like with the new exhaust/rebuilt carbs . . .


Carpy's THE MAN!

I was wondering about the exhaust on your CB 750, I heard a sound clip in a post about another 77' CB 750.  Sounds great, is the header Carpy's own or just the muffler (canister)?

[JAG]

+1 on the exhaust???

Is it the yamiya??

Also how does you knees fit into the inserts? Is it comfortable for you?

I know when doing mine, I had to come back (dent in) further towards the back so I would have a better transition from my thighs to my knees. Plus my knees went in fine but the back portion of the insert was poking into my thigh. I worried about going back the far, as it may have caused a crease, or sharp point in the tank, but it didn't. I wanted mine to be more functionality than looks.

But if you like it and it's comfortable for you, have at it.

Good job on the build, I'll be watchin

[Johnny5]

Hey Jag,

Dont know if you're asking me questions, or Duganc, but my exhaust is a Mac. I actually think it sounds pretty good.

As far as the knee dents go, Im not sure. Right now its mostly for asthetics and until I get a seat on, I wont know how functional they'll be. When I sit on the bike, my knees do cradle inside the dents, so Im sure it helps some.

As soon as my camera is filled with fresh batteries, I'll have a bunch more pics. The bike is now down to the frame as I wait for my sandblaster to arrive in the mail.

[cafeconleche]

Johnny, what kind of exhaust is that

i dig it

[Johnny5]

I believe it's the cheapest aftermarket exhaust you can find for the CB. Mac. I would like to throw a smaller baffle on it, but dont really know what's out there.

[JAG]

Well there this exhaust, but I was talking about



That one.. The headers look the same, but the muffler/tip looks different.. And I thought at first glance it was a yamiya.

JAG

[Johnny5]

So here's the bike just before I took it down to the frame. I experimented with color and quickly painted the side cover to get an idea, and I like it so much, Im going to go with silver/black/chrome for the color scheme. I have a sandblaster in the mail and soon I'll have some updates with some parts painted and the process of getting this machine back together.