Repair / Repairs / Tighten and adjust mirrors

Repair

Tighten and adjust mirrors

Rider jobNo special toolsTime: 10 min (estimate)

Mirrors let you see traffic behind before you change lane or turn. A mirror that turns in the wind or blurs with vibration is nearly useless. Most mirrors screw into the lever perch or a clamp on the bar and are held by a locknut; the head often has its own ball joint.

Safety

  • Adjust the mirrors with the bike stopped, never while riding.
  • Many countries require two working mirrors. Use mirrors approved for road use (the K-Light mirror carries an E-mark approval).

You need

  • The spanner or Allen key for the mirror stem locknut or mounting bolt. K-Light 125 mirror bolt (Allen M8 × 50): 22 to 29 N·m.

Steps

  1. Sit on the bike in your normal riding position, bike upright.
  2. Find which part is loose: the stem in its mounting, the stem locknut, or the ball joint at the head.
  3. Stem loose: turn the stem to the angle you want, hold it, and tighten the locknut against the mounting. On some bikes one mirror has a left-hand thread: if the stem will not screw in the normal way, try the other way, gently.
  4. Ball joint loose: some have a nut or screw at the joint; tighten it until the head moves only with firm hand pressure. A worn joint with no adjustment means a new mirror.
  5. Set each mirror so you see the lane behind you and just a little of your own shoulder or arm at the inner edge.
  6. Check the mirror does not hit the fuel tank, screen or your hands at full lock.

Check your work

  • Mirrors stay in place at speed and over bumps.
  • The view is clear, not blurred. A blurred image at one engine speed can mean missing bar-end weights (K-Light 125 bar-end weight screw: 10 to 12 N·m) or engine vibration: New or increased engine vibration.

If it did not fix the problem

Reference values (K-Light 125)

Item Value Source
Mirror bolt, Allen M8 × 50 22 to 29 N·m K-Light 125 manual, PDF pp. 131, 135
Bar-end weight screw 10 to 12 N·m K-Light 125 manual, PDF p. 145

Problems this repair helps with

Sources
  • K-Light 125 manual, PDF pages 131, 135, 145, 49

Values marked K-Light 125 are for that reference bike. Use your own bike's manual for its values. Text CC BY-SA 4.0, Transitions Lab.