Speedometer needle moves when revving stationary - BMW F800 Riders Forum & Registry



Remove this advertisement by REGISTERING.

Results 1 to 5 of 5
  1. #1
    Points: 8, Level: 1

    Joined
    Sep 2020
    Online
    4 Weeks Ago
    Posts
    1 / 0 / 0 / 0
    Hello ladies and gentleman, my first post here, been reading the forum for years. English is not my best language but i try my best. I have a question abaut first generation f800r, so here goes: when you turn the key, warning lights light up, everything comes to life, all is normal, but both needles twitch a little before you fire it up (maybe even when engine running, not sure)? The self test is fine, both needles go to full position and back. After that, when engine is running, if i rev it, also the speedometer needle goes up to like 20, 30 km/h. When i release the throttle to idle it comes back to 0. The RPM needle is ok, moving with engine RPM....but why the hell is speed needle moving if bike is stationary?? Fact is battery is old and weak, can that be the problem? Bike has both wheels on the ground, no centerstand. So basicaly why do needles twitch when you turn the key and why is speed needle going up when revving when the bike is not moving?

    Thanks a lot for your answers.
    Last edited by FatAndFurious; 4 Weeks Ago at 06:10 AM.

  2. Remove Advertisements
    F800Riders.org
    Advertisements
     

  3. #2
    Runmyownlife's Avatar
    Points: 14,839, Level: 83

    Real Name
    Andrew
    Location
    Calgary, Alberta
    Joined
    Feb 2017
    Online
    7 Hours Ago
    Posts
    1,041 / 0 / 0 / 0
    Motorcycle
    '08 F800 ST
    Motorcycle
    '08 F800 ST
    First, your written English is excellent. Better than some folks with English as their first language.

    Second, I love your user name. Quite witty and solid use of English demonstrated.

    With respect to the issue - it's a first for me. Electrical is not my initial thought. An electrical issue would usually presents as a speedometer and tachometer that does not move. The speed is measured at the rear wheel through the ABS system. You'll notice by the brake rotor a ring with evenly space gaps. This interupts a small magnetic field created by a sensor placed near the caliper.

    Perhaps the sensor is faulty and providing erroneous information. I can't offer an easy or cheap way to test this. The cable runs from the rear wheel, along the frame to the centre of the engine area. It's tight! A used sensor may be $30 to $50?
    Concrete remains undefeated. 

  4. #3
    ccramerusc's Avatar
    Points: 8,684, Level: 64

    Real Name
    Cramer
    Location
    Milwaukee, WI
    Joined
    Jun 2013
    Online
    16 Hours Ago
    Posts
    724 / 0 / 0 / 6
    Motorcycle
    '08 F800ST
    I agree with everything Andrew said. The sensor would be my first guess, but it is only a guess. I've never heard of this happening. Maybe remove and clean the sensor?

    I'll add that I seriously doubt that it is battery related.

    Sent from my SAMSUNG-SM-G891A using Tapatalk
    08' F800ST- side panniers & Shad SH45 top case, Russell Day Long seat, MRA Vario Windscreen, SW Motech crash bars, ZTechnik exhaust, PC-8 fuseblock, Stebel Nautilus horn, Throttlemeister throttle lock, SW Motech handlebar risers, LED fog lights, highway pegs 

  5. Remove Advertisements
    F800Riders.org
    Advertisements
     

  6. #4
    Points: 6,915, Level: 57

    Location
    Lansing, Kansas
    Joined
    Aug 2012
    Online
    10 Hours Ago
    Posts
    388 / 0 / 0 / 6
    Motorcycle
    '12 F800ST
    Welcome from the coast of Kansas, USA. Glad you found this forum and have decided to hop in.

    Someone here will have an answer to your question, but not me. I am not a fixer, i am simply a rider. And since the twitchiness of the speedo needle does not affect your riding, don't worry about it. Ride the wheels off the bike and have fun!
    Royce
    On the coast of Kansas
    2012 F800ST
     

  7. #5
    Points: 2,609, Level: 33

    Real Name
    Matt
    Location
    Carlisle, PA
    Joined
    Jan 2018
    Online
    1 Week Ago
    Posts
    36 / 0 / 0 / 0
    Motorcycle
    '13 F800R
    While swapping out my rear tire, I had to remove the sensor - you wouldn't believe the amount of tiny metal bits stuck to the magnet. I second cleaning the sensor.
    My 2013 R goes through the initial systems/gauge check upon turning the key, then randomly does it again after firing her up - probably 1/12 times. I do have the original battery in it still, so my battery may be going.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •