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Solved Help Virago speed limited ?

Discussion in 'Technical and Troubleshooting Torque' started by Woodlea Park, May 16, 2016.

  1. Hi I just bought a Yamaha Virago 1986 xv750 imported from Japan with 13000ks on the clock

    Passed RWC last week and are waiting on club rego documents
    Hubby took it up the road this arvo and the speed warning light on taco comes on at 80km and its a real struggle to get her to 90kph
    Runs perfect until 80kph then just nothing there like it is speed limited

    Has anyone else come across this issue

  2. this may help with "adjusting" the speed warning light (if speedo setup is same)
    Speed warning light at 80KMH.

    you may get some love from the Viragotech forum, but need to register
    ViragoTechForum.com • Login

    can't quickly find any reference to an actual speed limiter

    if the speedo light comes on by the same method as in the first link, then unlikely the bike has an electronic speed limiter, and may just be running out of puff due to carby size/settings
    • Like Like x 1
  3. Thank you
    We were thinking about that. We have contacted the seller /importer and he is looking into it also
    Cheers Colleen
  4. The silly thing is it runs perfect and as it should until you hit 80 then it just has nothing else
  5. It could be retarding the ignition if its reving freely below it.
    Can you disconnect the speed sensor and give it a blast?
    • Like Like x 1
  6. Can get Hubby to try that
  7. 81-83 US model diagram doesn't show any speed sensor, or way for it to limit speed.. but may be different for JP 86 model...

    do you have a wiring diagram or manual already?
    • Like Like x 1
  8. Unlikely to have a speed limiter. Good chance the needles are too far down in the vacuum slides in the carbies though. That will result in a fairly normal lower mid-range but no top end at all (leaned out).
    • Like Like x 1
  9. Cant find any reference to it in the diagrams
    Thinking it maybe a carby issue but more investigation needed

    Can't even work out at the moment where or should I say how the speed light is activated at 80km. Light is on tacho so not triggered by speedo needle
  10. is there a wire or wires coming out of the speedo?
    will keep looking

    ed: that diagram, on left in the gauges there is "Speedometer sensor"..
  11. Are the butterflies in the Carby opening up all the way when you pull on the throttle? (Check with engine off).
  12. #12 Returned, May 17, 2016
    Last edited: May 17, 2016
    Reminds me of a V8 I had once. Ran well around town but struggled to get to 100kph on open highway - but I could rev the motor. It was a fuel filter blockage. Under load over a distance it wanted to suck in more gas than a brief revving of motor, but could not because of blockage.. As soon a fuel was used up in float bowl it would not replenish/keep topped up quickly enough at speeds above 80-90kph. I gather you have tried holding throttle open at high revs for more than just a blip to check fuel flow.
    • Like Like x 1
  13. Does it go to near redline in the low gears but wont go past 80 on the road in any gear?
  14. I will get hubby to check as I am at work all week
  15. I will ask hubby as I haven't ridden it out of 1st yet. He said it road like normal until 80k then just had no power or pull above that in either 4th or 5th
  16. Hubby spoke to the importer who is going to make equiries
  17. $_57 (9).JPG
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  18. $_57 (7).JPG
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  19. I would check the fuel supply as well. Maybe clogged or dirty filter
    • Agree Agree x 1
  20. With my scooter was speed limited with the mechanical speedo cable sending the speed to the dash then from their sending a limiting signal via a single wire to the cdi.
    To diagnose this I disconnected the speedo cable from the front hub then once confirmed limiting took place probed the dash.and cdi plug for continuity before clipping the magic wire.

    When it was coming into restrictions it just felt more like fuel exhaustion then the redline limiter. Another thing to look at is the airfilter to ensure its not clogged up
    • Agree Agree x 1