1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

Speed warning light at 80KMH.

Discussion in 'Hangout Lounge' started by sanglasmick, Dec 16, 2013.

  1. sanglasmick

    sanglasmick Member

    Messages:
    106
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Wexford, Ireland
    Hi guys,

    I have a 1981 XJ750A with 55k kms on the clock.
    Because its a Japan only model there is a speed warning light which comes on a the bottom of the speedo at 80kmh and stays on at any speed higher than that.

    I am wondering does the clock have the same system as some Hondas do, of having like a paper disc which rotates with the needle inside the clock to turn on the light? I had a CBR750 which had this system and was able to "adjust" when the red light came on by cutting a section of the disc away.

    Some say I could just remove the bub, but I think a warning could be useful, but only at higher legal speeds here in Ireland, like 120kmh on the motorway. Then I wouldn't mind having a warning light! It's better than a ticket.

    Any help would be appreciated.
     
  2. TIMEtoRIDE

    TIMEtoRIDE Active Member

    Messages:
    4,686
    Likes Received:
    10
    Trophy Points:
    38
    Location:
    Clermont FL near Orlando
    Japan actually had a Nation-Wide speed limit of 50 MPH and a maximum motorcycle displacement of 750 CC. Along with a graduated motorcycle license, named intersections, but not named roads, and public bathrooms where you sort of . . . I won't get into that.

    Removing the bulb would be a good fix.
     
  3. sanglasmick

    sanglasmick Member

    Messages:
    106
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Wexford, Ireland
    Thanks Timetoride, I thought that was a bit easy!

    I need to strip and repair the speedo anyway so I'll see if there is the disc I mentioned and post pics if I can.

    Cheers,
     
  4. 750E-II_29Rbloke

    750E-II_29Rbloke Active Member

    Messages:
    1,955
    Likes Received:
    4
    Trophy Points:
    38
    Location:
    South Cheshire, UK
    I know there's a reed switch that is used by the self-cancelling indicators, perhaps that could also be used by the speed light (illuminating when the reed switch goes above XX cycles per second or something).

    I'll have a look in my spare E-II clocks in a minute, you got me wondering now haha EDIT-: Has got to be reed-switch operated on mine, that's the only 2 wires that go to the speedo so has to be through that I think... Sadly if yours is the same Mick, that means the only way you'd be able to re-calibrate it would be either reflash the chip that controls it (practically impossible) or use a mechanical Km/h to Mph convertor on the cable. This would give you a speedo that read in Mph (up to 180Mph if it's same as mine!) and a speed warning around 80Mph. Bit more useful for our roads I guess.
     
  5. cds1984

    cds1984 Active Member

    Messages:
    902
    Likes Received:
    195
    Trophy Points:
    43
    Location:
    Perth, Western Australia
    The police digital meter uses the reed switch for the pulse and also has a set of 3 or 4 dip switches inside to adjust/calibrate it.
    You'd think they would have implemented some calibration within yours to alter that warning light. Worth taking a look for sure.

    Hopefully!

    After all I do like a good warning light!
     
  6. bmarzka

    bmarzka Active Member

    Messages:
    463
    Likes Received:
    61
    Trophy Points:
    28
    Location:
    Northwesten PA on Lake Erie
    When it comes to speed, the only warning light I have sits on top of 4 wheels. And by the time I see it, it's TOO late. (Thank you, sir. May I have another?) Gotta hate radar.
     
  7. sanglasmick

    sanglasmick Member

    Messages:
    106
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Wexford, Ireland
    Sorted!

    Over the weekend I finally got to open up my speedo head and repair the stuck needle.

    While in there I also adjusted the speed warning light. It used to come on at 80KMH, a real pain. It now comes on at 125KMH, when I really need a warning. In Ireland the max motorway speed is 120KMH so a light at 125KMH could save my licence. I have photos but can't seem to attach them to appear in the post.

    As I suspected there is a thin aluminium plate which rotates with the needle, as this plate rotates it has a larger diameter section which goes between two sensors bringing on the light. I simply held the needle where I wanted the light to come on, and trimmed the disc with a small scissors. I removed a piece about 18mm long on the outer edge. I had seen the same system on a 1989 CBR750 Honda. The pictures were take with my phone, but should be OK to explain the system.


    http://s1156.photobucket.com/user/sangl ... .jpeg.html
     
  8. sanglasmick

    sanglasmick Member

    Messages:
    106
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Wexford, Ireland
  9. mtnbikecrazy55

    mtnbikecrazy55 Active Member

    Messages:
    2,620
    Likes Received:
    24
    Trophy Points:
    38
    Location:
    Green Bay, Wisconsin
    Neat! How'd you figure out how much needed to be cut?
     
  10. bigfitz52

    bigfitz52 Well-Known Member Premium Member

    Messages:
    21,283
    Likes Received:
    415
    Trophy Points:
    83
    Location:
    Rural SE Michigan 60 miles N of Motown
    The whole thing is ingenious as heck and yet another tribute to Yamaha's "parts room engineering." Here we have the ubiquitous Yamaha mechanical speedo, and all they did was add the thin disc and scab that little circuit board with the photosensor on it onto the outside rather than redesign the whole instrument.

    The irony of it is that it only warns you based the position of the speedometer needle, not how fast the bike is actually going. And everybody who's ever fought with a gummed up Yammie speedo knows that those two things are not always one and the same.

    Neat "farkle" though. My VW has a programmable "speed warning" feature; I wonder if it's a requirement in some parts of the world?
     

Share This Page