'78 CB400T POS

tenaciously96

New Member
I'm a little behind on posting the build so I'll try and catch up...

Here's how she was when I got her -- wrecked with bent forks and swing-arm.

A little back story if your interested --

I bought the thing for $400 bucks from some kid from Wisconsin. It still had the out of state tags and it was a absolute pain-in-the-ass to get it registered in LA. Anyways, I replaced one of the forks and the swing-arm, changed the oil a rode the hell out of it for 6 months. Then, feeling inspired by all you guys on DTT and with daily feeds of bikeexif and pipeburn taunting me...I decided that I had to cut it up. I'll keep a log of the progress here. I have some experience working on older cars (first car was a 1967 Ford Fairlane), but not a lot of moto experience. I'll have to depend on you guys for your expertise...
 

Attachments

  • 20130603_214520.jpg
    20130603_214520.jpg
    103 KB · Views: 377
  • CB400TII_Left.jpg
    CB400TII_Left.jpg
    3.9 MB · Views: 289
I picked up an early 70's CB350 and a CB450 tank. The 450 fit the frame better, but it just seemed too big for the build. The 350 tank didn't fit at all! I had to modify (aka bang the shit out of it) to get it to fit over that weird "hump" in the center tube. The mid and early frames on these CBs were beautiful...why the hell did they change them in '78? Was it cheaper? Did they use less metal? Lighter? I don't get it...
 

Attachments

  • 20130904_124606.jpg
    20130904_124606.jpg
    72.2 KB · Views: 1,344
  • 20131214_181615.jpg
    20131214_181615.jpg
    107.7 KB · Views: 349
  • 20131214_181628.jpg
    20131214_181628.jpg
    89.6 KB · Views: 351
Here's the tank de-rusting using electrolysis. Supposedly you need a descent amperage charger to pull it off, but I used a trickle charger hooked to a battery -- and then connected the leads to the tank and the "scrap metal". One thing I did learn is that it definitely makes a difference when using washing soda vs. baking soda (sodium carbonate vs. sodium bicarbonate). The "carbonate" worked a lot better.
 

Attachments

  • 20131215_111726.jpg
    20131215_111726.jpg
    111.2 KB · Views: 1,374
The 400 has a stressed member frame (the motor being the stressed member) which is quite a bit stiffer tham the crappy stamped steel early CB frames.
 
Pulled the motor -- that thing was disgusting! I cleaned it with Zep Commercial Degreaser. This shit is legit. It'll burn the hell out of your skin and eyes so you know it's good.

I took the heads off and scraped old gasket off for 2 days...those thing were burned on and it was bullshit getting that crap off of there. I used a few flat chisels to scrape, but it was pretty challenging to not damage the aluminum. Is there a better way to do this? I dunno...

So, I installed new gaskets and put it back together:
 

Attachments

  • 20140215_171925.jpg
    20140215_171925.jpg
    121.1 KB · Views: 1,457
  • 20140209_115047.jpg
    20140209_115047.jpg
    122.4 KB · Views: 346
  • 20140208_161832.jpg
    20140208_161832.jpg
    140.7 KB · Views: 1,377
I screwed up and didn't paint the motor while I had it apart. I'm not sure why I did that...

I was thinking of painting the covers gloss black and the heads or fins flat black and leave the rest the crappy oxidized aluminum. I really want to make sure that I'm keeping to soul of the bike in tact. I hate vintage bikes that look brand new. Any ideas on so minimal engine paint schemes or "re-finnishing"?
 
Here is were I stand today. I hacked off that hideous ass-end and welded on my "custom" loop. I ordered some straight DOM tubing on Ebay. I made a bending "jig" out of particle board and heated and bent the straight tubing around the jig using my Oxy-Acetylene setup. The fact that you can bend AND weld with a torch setup is why it's my favorite. And, its way more fun to do than stick or mig.

I used the "slug" technique to connect the old tubing with the new. It feels stronger than the original. Here's an explination if your interested: http://dirtygursmetric.blogspot.com/2012/04/slugging-bout-damn-time.html

Any thoughts on the loop? I'm concerned that its a little low, but I tried to follow the line of the bottom of the tank. It's hard to tell at this point. I'm expecting to have to get taller rear shocks to match up with the new loop.

Still need to fab and weld the braces from the lower frame...
 

Attachments

  • 20140208_120410.jpg
    20140208_120410.jpg
    130.5 KB · Views: 1,366
  • 20140215_171918.jpg
    20140215_171918.jpg
    112.4 KB · Views: 1,428
VonYinzer said:
The 400 has a stressed member frame (the motor being the stressed member) which is quite a bit stiffer tham the crappy stamped steel early CB frames.

Well...I'm sure that I completely screwed the integrity of the design. I'm trying to follow the 'fail-safe' techniques to build the rear-end -- hope it turns out...

Thanks for the reply!
 
Looks good so far and it allows you to make 2 more improvements. First, you can replace those ugly, inefficient curved tubes that run from the swingarm pivot to the upper shock mount with straight pieces of tubing. It will be stronger, lighter and as a bonus, look better. Second, you can replace the upper shock mount with a stud and do away with the double clevis type shocks. That will give you a much better selection of available rear shocks. Since you have it apart and have the torch and skills, I would replace the lower shock mount with a U channel with 3 mounting lower bolt holes so you can use eye to eye shocks and have some adjustment for length and angle built in.
 
ex119x said:
Looks good so far and it allows you to make 2 more improvements. First, you can replace those ugly, inefficient curved tubes that run from the swingarm pivot to the upper shock mount with straight pieces of tubing. It will be stronger, lighter and as a bonus, look better. Second, you can replace the upper shock mount with a stud and do away with the double clevis type shocks. That will give you a much better selection of available rear shocks. Since you have it apart and have the torch and skills, I would replace the lower shock mount with a U channel with 3 mounting lower bolt holes so you can use eye to eye shocks and have some adjustment for length and angle built in.

Funny you say that -- I was just looking for double clevis shocks and they are few and far between. This sounds like good advise. It looks like it's 14" from eye to eye. Is this a "standard" size? I've seen a ton of 13" (which is the same length as the stock ones) but less of the 14s. Can you think of any downside to going with a longer shock? I guess that I don't really have a choice...

The adjustable U channel is a good idea. Any example links?

Here's today's progress. It ain't perfect, but it ain't half bad either:
 

Attachments

  • 20140216_142158_resized.jpg
    20140216_142158_resized.jpg
    94 KB · Views: 346
  • 20140216_143254_resized.jpg
    20140216_143254_resized.jpg
    77.1 KB · Views: 351
Once you weld a nice gusset in for the shock mount those will be plenty long.

And you run out of gas doing any kind of quality welding ;)
 
SONIC. said:
Once you weld a nice gusset in for the shock mount those will be plenty long.

And you run out of gas doing any kind of quality welding ;)

Man, I'm def gonna do that just so I can say 'gusset'...BTW I wish that I saw your seat hoop deal before I started. That's a solid, man. I'll look you up on the next one if your still doing em...
 
Sorry I don't have a picture of mine. It was done on my CB350 racebike so I could pick the best angle for my shocks. I had the swingarm lengthened by 2" and the top shock mount redone. I needed the lower shock mount set up for an eye since Ohlins doesn't do a clevis mount in that shock. Randy Illg at Framecrafters in IL did the work for me.

My garage is 4000 miles away from me and I won't be back there until June or July.
 
ex119x said:
Sorry I don't have a picture of mine. It was done on my CB350 racebike so I could pick the best angle for my shocks. I had the swingarm lengthened by 2" and the top shock mount redone. I needed the lower shock mount set up for an eye since Ohlins doesn't do a clevis mount in that shock. Randy Illg at Framecrafters in IL did the work for me.

My garage is 4000 miles away from me and I won't be back there until June or July.

Wow! 4000 miles? You should be having withdrawals by now. Well, thanks anyways -- I'll see what I can come up with. I think that I need to do a "gusset" as suggested before...I just need to find the right gauge steel to do so. Dime City has a "universal mount" but I'm not sure how great it is...and they show a picture with a cross member connecting the two studs:
dcc-smount-vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-chassis-shock-parts-dcc-originals-diy-shock-mounts-2.jpg

vintage-cafe-racer-caferacer-custom-motorcycle-honda-shadow-vt800c-dime-city-cycles-payback-50_1_1.jpg


I don't know if I'll have tire clearance for all that with the stock swingarm...anyways, hopefully some ideas will come...

(The frame build on this dime bike is making me feel better about my welding job)
 
Those posts look like they should work fine.
I exaggerated about how far it is to my garage and racebikes, too. It is really only 2,768 miles according to Google. I do get a little fidgetty without my good bikes for 10 or 11 months a year, but I have a couple of small dirtbikes and a snowmobile to play with here.
 
It's been slow going trying to find the balance between progress and divorce ;)

I got the motor painted, but I'm not pleased enough with it to post a pic for you guys.

I did, however, find the time to get the top of the triple and forks stripped and cleaned. Waiting for I've found to be the elusive maroon scotch brite to arrive in the mail so I can 'brush' the bare aluminum to a matte finish. I'm slowly realizing how much time it takes to build a moto from a ground up break-down. Shit! Anyways...any progress is progress. Right?

Here's the picks:
 

Attachments

  • 20140219_214521_resized.jpg
    20140219_214521_resized.jpg
    425.9 KB · Views: 970
  • 20140219_222043_resized.jpg
    20140219_222043_resized.jpg
    367.1 KB · Views: 322
Ya bike building is nothing but slow progress... Either your waiting fix/clean one part or waiting on UPS for another part! But hey it makes the fun last longer!

Also id that the stock triple tree clamp? If so it looks grate for stock very simple and clean.
 
Back
Top Bottom