1984 CB700SC Nighthawk - first rebuild

Discussion in 'Old's Cool' started by Merfman, Nov 30, 2012.

  1. Goggles Paisano

    Goggles Paisano La Muerte Peluda

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    Entropy isn't what it used to be
    I like this thread. My bike is an 85 750s, the Canadian version of this bike in red and black. I wanted the black and blue, but beggars can't be choosers.
    #21
  2. Merfman

    Merfman Trustin' my cape...

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    Got a working neutral/shift switch? Mine appears non-funct. I need to pull it and see if there's any rebuild potential but a cursory ohmmeter exam today indicated it was open. Could just need cleaning but I thought I'd touch base and see if you have one just in case...
    #22
  3. Merfman

    Merfman Trustin' my cape...

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    Today - that pesky gear switch selector! Previously I'd checked the switch for continuity and discovered all contacts were open and indicated a required removal for inspection. In true Murphy's law fashion, the bottom left mounting screw didn't just pop out. The kickstand and shifter needed to be removed so I could get an impact driver on the stubborn screw. Of course, removal of the sidestand and shifter did nothing to ease access to the buggered screw. The spring mounting post is the problem and it's welded to the frame. Oh well, looks like it needed cleaning anyway...
    [​IMG]

    After a couple of false starts, I was able to get the screw out and the switch removed. When I pulled the pickup out of the cavity, the problem was pretty evident. Looks like I got one too many pieces:
    [​IMG]

    Not only was the post broken, but the wiring inside was buggered as well. Looks like it's been broken for while...
    [​IMG]

    So, I've got the carbs out and awaiting a replacement for the clay gas tee and now I need to order a replacement gear indicator switch... remembered the side stand looked like it needed cleaning. Scrubbed it up in the parts washer, and immediately feel like I've accomplished something! I can't fix anything to so crank up the tunes and find some rags! Time to clean! Something about working on a dirty bike kinda kills the mood. A good cleaning will really tell me what I've got...and. . I was stoked by what I found, the bike has excellent bones. Patinaed bones, but excellent bones nonetheless. A few teasers:

    Before:
    [​IMG]

    Afters:
    [​IMG]

    [​IMG]

    [​IMG]

    Lastly, as the day grew to a close and I had a couple beers..
    [​IMG]


    There are 576 1984 Nighthawk CB700SC items for sale on FleaBay today. Not a single one was a gear selector switch or a replacement fuel line T. This indicates a surplus of gorilla 700SC mechanics and perhaps a faulty design.

    Lastly, a first. SILTHW count today = 0

    Happy New Year YFF's!
    #23
  4. Lomax

    Lomax Nanu-Nanu Adventurer

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    I have no idea if yo will run into this or not, but I will share my grief. My 84 ran fantastic over about 3000 RPM but misfired badly below that. After months of doing this and that I found one of the coils to be bad. Just a heads up. GOOD for you bringing it back to life. :clap

    Marc
    #24
  5. Merfman

    Merfman Trustin' my cape...

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    Thanks Marc! I revved it up pretty good when I first got it running and it seemed to run pretty drama free. I'm sure I cured that with my carb clean. ;) Pushing up on the slides with my finger indicated that two of the carbs act differently than the other two tho, I might be re-doing that particular job. Part of the process eh?

    In any case, thanks for the heads-up! We should have a beer when I get the 'Hawk roadworthy.
    #25
  6. Happy Seal

    Happy Seal Long timer

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    Where are you guys getting parts. Does Honda stock any oem parts like the complete sticker sets? I picked up an 85 700SC yesterday!
    #26
  7. divotdm

    divotdm Been here awhile

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    #27
  8. Merfman

    Merfman Trustin' my cape...

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    #28
  9. 1f2frfbf

    1f2frfbf full-time fool

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    FYI on the gear switch, I got lucky finding one for my Yamaha by taking the old one to a friendly, old-skool, 4 wheeler shop and comparing them. Found one in their old stock that fit my bike from off a similar vintage four-wheeler. Oftentimes the manufacturer would just order a huge batch of them and use them for everything but slap different part numbers on them for 2 wheels or 4 wheels, but same bit of metal. I know Honda used similar seals between marine and terrestrial motors... Dunno if this helps you, but one more avenue to check.
    #29
  10. Merfman

    Merfman Trustin' my cape...

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    That's great info! Thanks for passing that along, I'm not sure I would have thought of that!
    #30
  11. grindz145

    grindz145 Gangster.:D

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    Hey man, Just happen to stumble over your thread. I actually have like 3 spare motors for my Nighthawk S I may very well have a spare shifter switch if you need one. Drop me a PM if you're interested.
    #31
  12. Merfman

    Merfman Trustin' my cape...

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    Thanks grindz! I'll keep you on speed dial. I'm currently awaiting my parts before digging further into the bike. Waiting on the carb "T" and the gear selector switch before starting on the forks.

    Thanks for all the hints and offers everyone!
    #32
  13. McJamie

    McJamie STROMINATOR

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    I also had one, an 84 750. If you have the stock exhaust, keep it. The bike will run stronger, smoother, and sound way better with the stock set-up than anything else you could put on there. Also make a VERY close inspection of the intake manifolds. They will have dried, and potentially cracked given the age of the bike. Sucking in even a tiny bit of air will affect the bike's performance. I replaced mine twice.
    To be honest, I never really cared for mine much. I didn't like the handling, I found it rather twitchy.16" wheels likely why. I had just come from a GPZ 750 which with it's taller wheels and longer wheelbase was a freight train in comparison. The Honda was smoother than the GPZ, which is really saying something. I also tried slightly lower handlebars getting more weight over the front which seemed to help a bit.
    Don't buy cheap or shit tires. Grip is everything with this bike.
    A well set-up, good running model, is about as maintenance free bike as you can get.
    #33
  14. jrswanson1

    jrswanson1 n00b

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    I've got an 85 version of your bike. I just ordered new clutch plates for her, since the ones in now are going. I hope you've changed the oil already, the valves use oil to maintain the proper gap. I really hate the gearing on these bikes. Who decided that it was okay to be in 4th gear at 30 mph? Anyway, check out the Nighthawk forum if you're looking for parts and answers on your bike. Good folks, very knowledgeable.
    #34
  15. Merfman

    Merfman Trustin' my cape...

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    Thanks everyone! I'm Merfman over on the nighthawk-forums as well. You're right, great bunch of guys over there! My intake boots are pretty hard but don't seem to have any cracks in them so I'll play that one by ear. I'm not keeping this bike as a daily commuter, I have a much-loved Super Tenere' for that, this bike is a winter project intended to gauge my skill, patience and interest in refurbishing neglected machinery. I intend to ride it for a while after I get it roadworthy and unless I fall in love, it'll be on the blocks in the Spring.
    #35
  16. Kriton

    Kriton n00b

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    Hello, I just found your thread and am looking on in earnest. Many years ago I hit a deer with my Nighthawk ( and unlike others I did not cut the deer in half and keep going). I was wondering if you are going to change the cam timing or switch to a K&N filter with carb adjustments. I saw an old article somewhere on the internet that I can no longer find that described the whole process. I am intending to replace the head with an new one because of some broken fins. I've gotten to the point where the bike is actually referred to as a classic and it would be nice to get rid of the unsightly scars.

    Good luck on the rebuild and I will be following
    #36
  17. Merfman

    Merfman Trustin' my cape...

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    Hi Kriton! My bike came with a K&N filter and I think it had already been rejetted but I"m not sure. I still have the carbs off the bike so I need to check that... I had no plans to change the cam timing. I've started the bike and it seemed to run just fine so I'll be changing as little as possible!
    #37
  18. Kriton

    Kriton n00b

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    #38
  19. Merfman

    Merfman Trustin' my cape...

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    My parts came in last Thursday! :clap There seems to be a conspiracy afoot however... the Broncos play today at 2:30 and it's 0 outside. I'm not sure my heaters can overcome the momentum of the cold and my desire to be couchbound while watching the game! Hopefully it'll warm up a little tomorrow and I can start reassembling some stuff...

    Oh yea, SX live on Speed tonight. I'm not gonna get much done today.... :freaky
    #39
  20. Merfman

    Merfman Trustin' my cape...

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    Too many distractions of late but I did get my seat back. I couldn't resist a test fitting. [​IMG]

    This weekends forecast looks good but maybe not good enough to go riding so maybe progress can be made once more.

    Well, the forecast was good but unfortunately, I had to make time to attend a funeral 850 miles away. Perhaps this weekend...
    The wintergreen I ordered came in and I'm picking up some Xylene locally so things *are* coming together, albeit very slowly.
    #40