Speedo

Discussion in 'Tech Area' started by Dennis McDonaugh, Mar 24, 2020.

  1. Dennis McDonaugh

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    I've gotten around to cleaning and checking the speedometer. It seems to work correctly - I connected a drill to the cable and it registered up to 20 mph. I checked the bulbs and the red light and the instrument lights work, but the neutral light is burnt out. I'd like to clean the glass, but don't know how to get the unit apart.

    I used a battery charger to test the bulbs.

    IMG_2968-L.jpg

    How do I disassemble the cluster? I removed the three small Philips screws, but it didn't see to fee anything.

    IMG_2969-L.jpg
     
    #1 Dennis McDonaugh, Mar 24, 2020
    Last edited: Mar 24, 2020
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  3. hrc200x

    hrc200x Active Member

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    Under the rubber boot around the face of the glass is a chrome ring, that ring needs to be uncrimped to get speedo apart. I don't know if anyone has made a useful tool in helping with that process. It needs to be recrimped to assemble so take care not to damage taking apart
     
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  4. hrc200x

    hrc200x Active Member

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    Just found this video, watching it now to see how useful it maybe:
     
  5. Dennis McDonaugh

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    That helps a lot. I think all Honda's are like that. I guess they don't want you messing with them. I had to replace a needle on a 1983 CB1100F and it was exactly the same.
     
  6. Dennis McDonaugh

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    That black ring is as inflexible as steel after almost 50 years. I'm thinking I'll have to cut it off to get access. I won't do that until I have a replacement.
     
  7. kirrbby

    kirrbby Well-Known Member

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    Heat it up really good with a hair dryer or carefully with a heat gun. Heat, on old rubber, almost always works to soften it up, temporarily.
     
  8. racerx

    racerx Administrator
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    The plastic outers can develop arthritis after 48 years. As I recall, however, CHP listed a reproduction (last time I looked)...you might want to check there first, before reaching for a blade.

    These round speedometers are a lot tougher to restore than the triangular K0/HK0. The stainless outer bezel is a lot thinner than the 0.015-0.017" thick K0/HK0, the crimping is tighter, the edge shorter and there's no good place to "grab an edge". On top of that, keeping the chrome scar-free is no mean feat. Once inside, the mechanism is anything but restorer-friendly. Clearly, neither Honda nor the OEM of these units ever intended for them to be opened & serviced. Nothing unusual there; how many speedometers were ever made to be serviceable? All of that having been said, it is possible...just a matter of time, talent and, of course, bucks. If you're only looking to clean the glass, then some metalworking talent, specifically hammer & dolly + polishing, is about all that's required to get a good result. Cleaning & zeroing-out the odometer depends on the unit. There are 2 different OEMs (Nippon Seiki, "HM") for both the K1 & HK1 versions of this speedo.The "HM" mechanisms are very tricky to work with. The Nippon Seiki graphics can be exceedingly fragile. If the graphics appear alligatored, under magnification, don't touch them...they've been UV damaged to the point where a damp cloth can nearly remove them. Forewarned = forearmed.
     
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  9. scooter

    scooter Well-Known Member

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    Picture of a tool I made from a Harbor Freight small adjustable wrench to get under the lip. I open the wrench to get under the lip then close it to pry. Patience as you work. Good luck
    B7FDF87A-8136-4711-B576-124BE3A8B4BB.jpeg
     

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