Mirror is loose or will not stay in place

A mirror turns in the wind, droops over bumps, or shakes so much that the image is blurred. Without a clear view behind, lane changes and turns become risky. Usually the stem locknut or the ball joint has loosened, the thread in the mounting is worn, or vibration from missing bar-end weights blurs the image.

Is it safe to ride?

With care. Turn your head to check behind until the mirror is fixed. Many countries require working mirrors.

Quick checks first

• Which part moves: the stem in its mounting, the head on its ball joint, or the whole lever perch?
• Is the stem locknut loose?
• Are the bar-end weights fitted?
• Is the glass cracked?

Diagnose it step by step

1Does the whole lever perch or clamp turn on the handlebar?

• Yes: tighten the perch clamp (Service brake and clutch lever pivots).
• No: go to step 2.

2Does the stem turn in its mounting?

• Yes: set the stem angle and tighten the locknut (Tighten and adjust mirrors). K-Light 125 mirror bolt: 22 to 29 N·m. Go to step 3 if it will not tighten.
• No: go to step 4.

3Does the locknut or stem spin without tightening?

• Yes: the thread is stripped. Fit a new mounting or a thread insert at a workshop, or a new mirror if the stem thread is damaged. Remember one mirror may have a left-hand thread.
• No: tighten and test.

4Does the mirror head move on its ball joint?

• Yes: tighten the joint if it has a nut or screw. If it has no adjustment and stays loose, fit a new mirror.
• No: go to step 5.

5Is the image blurred only at certain engine speeds?

• Yes: check bar-end weights are fitted and tight (K-Light 125 bar-end weight screw: 10 to 12 N·m), engine mounts tight, and see New or increased engine vibration.
• No: if the glass is cracked or loose in the housing, fit a new mirror of an approved type.

Causes, most likely first

Reference values (K-Light 125)