1975 Honda CB400 Supersport

Discussion in 'Old's Cool' started by Pablo83, Sep 19, 2012.

  1. Pablo83

    Pablo83 Sleep, Wrench, Ride

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    I picked up a CB400 SuperSport recently. It's in parts. It's had a cafe style body kit put on it.

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    #1
  2. plumber mike

    plumber mike Highdive Deepened

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    Very cool. There is a fella in Nederland with a mint one if you need reference on reassembly. He seems very knowledgeable about these bikes.

    If you give up on it and start offloading parts, let me know. My mom lives down in the springs, so I could justify a trip down to pick up parts.

    Best of luck with the bike either way. :freaky
    #2
  3. arapaho

    arapaho Been here awhile

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    I had one of those in 1998-9. Mine was entirely stock, and really a lot of fun.

    They're not all that fast, but they sure sound great when you're on the pipe.

    Parts are not cheap, and exhausts were hard to come by.

    It should be fun to put back together.
    #3
  4. Pablo83

    Pablo83 Sleep, Wrench, Ride

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    I made some room for it in the shop

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    The guy who was going to resurface the head for me is pretty backed up so I need to find someone else. I've got a couple referrals. I'll go down to CO Springs today and find a shop. I also have a bunch of parts on the way.
    #4
  5. Pablo83

    Pablo83 Sleep, Wrench, Ride

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    The exhaust has some pretty serious road rash on the right side pipe. I hear that most of these bikes ended up with damage to the right side pipe.
    #5
  6. Kurt V

    Kurt V Been here awhile

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    Mine is pretty much stock also in case you need some close up pics of anything. Good luck with the project!

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    #6
  7. Pablo83

    Pablo83 Sleep, Wrench, Ride

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    I appreciate that. It's likely that I'll need some help putting it back together at some point since I didn't take it apart. Any chance you know where I can get an electronic copy of a shop manual for it?
    #7
  8. JerryH

    JerryH Banned

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    The original CB400F Super Sport was a cool bike. Only stock bike of it's time that I knew about that came with a 4 into 1 exhaust. It came a lot closer to what I would consider a "sport bike" than todays crotch rockets, basically street legal roadracers. Another one of those bikes I wish I had owned but didn't. I figure my bought new '83 GPz550 came pretty close to it in feel and performance.
    #8
  9. IHWillys

    IHWillys Been here awhile

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    I have a '75 CB550F Super Sport that has the original 4 into 1 still on it in very good condition. I prefer the inline collector of the 400 over the square collector of the 550 though.

    Ken
    #9
  10. Kurt V

    Kurt V Been here awhile

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    http://forums.sohc4.net/index.php?topic=17788.0
    #10
  11. Pablo83

    Pablo83 Sleep, Wrench, Ride

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    #11
  12. Pablo83

    Pablo83 Sleep, Wrench, Ride

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    I've spent about four hours on the bike today. Compression on cylinder 3 was 55 PSI. I adjusted the valves (they were terrible) and compression went up to 110! Compression in all cylinders is now between 110 and 120. There was also a bad condenser for the left coil so I replaced that and a spark plug boot and she fired up! All I had in the shop was 2-stroke pre-mix so she made a lot of smoke. She also leaks lots of fuel out the carbs. It appears to be coming from between the bowl and and carb body on all four carbs which is weird because I just replaced all of those gaskets. Anyone else had this problem?

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    #12
  13. bmwhacker

    bmwhacker Still on 3 wheels

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    I found this "crispy" $100.00 speciman in rural NV. a few years back. The carb interiors were completely corroded from sour, ancient fuel. Decided to sell it since carbs were gonna cost way more than I paid for the bike. The new owner was pretty happy to take it for $300.00.

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    #13
  14. Pablo83

    Pablo83 Sleep, Wrench, Ride

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  15. Pablo83

    Pablo83 Sleep, Wrench, Ride

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    Now for the fun part: trying to figure out what other people have done to the wiring harness over the years.

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    I've found two wiring diagrams on the internet for this bike. Both of them show a single fuse for the system. My bike has a main fuse, plus a fuse box with with 5 fuses and more wires than either of these diagrams say I'm supposed to have. Can anyone point me to a correct wiring diagram for my bike (1975 CB400F)?
    #15
  16. Skowinski

    Skowinski Eukaryote

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    Afraid I can't help you with the wiring. :arg

    But, you are making me jealous. I picked up a complete, including stock exhaust, 75 model years ago, for only $250, and it was stored in various places for something like 8 years, untouched. I finally sold it, for $400, to some guys who were going to restore it. I was tired of looking at it, dirty and greasy and in need of help, and didn't see when I'd get to it. I regret that decision.
    #16
  17. Pablo83

    Pablo83 Sleep, Wrench, Ride

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    I found the problem:

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    I was also able to find a US model CB400F wiring diagram which matches the bike. I think I've fixed all the electrical issues.

    I see projects like this (just buckets of parts) for sale on Craigslist all the time and I always wonder what type of person would buy something like that. I would never get into something like this unless there were something really special attached to the deal. So I've got to admit I've been sandbagging a bit. I'll have pics soon...
    #17
  18. Pablo83

    Pablo83 Sleep, Wrench, Ride

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    Got the body panels on. The previous owner wasn't much of a mechanic, but he's pretty damn good with fiberglass and paint.

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    #18
  19. Kurt V

    Kurt V Been here awhile

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    Wow Pablo, you are making some great progress! Looks like you have Napolean bar end mirrors.
    #19
  20. Pablo83

    Pablo83 Sleep, Wrench, Ride

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    They look like Napolean's, but don't work as well. I'm not sure who makes them.
    #20