Ktm Sx 125 Common Problems
Known issues to inspect before buying a used Ktm Sx 125. What to check and how much repairs cost.
Top end wear, piston and rings
SERIOUSPull plug, check compression, listen for rattle
Fix cost: $150-$400
Reed valve deterioration reduces power
MODERATEInspect reeds for cracks or curling visually
Fix cost: $30-$80
Power valve seized or carboned up
SERIOUSRemove cover, check valve moves freely by hand
Fix cost: $50-$200
Worn or leaking fork seals
MODERATELook for oil residue on lower fork legs
Fix cost: $80-$180
Pre-Purchase Checklist
☐Check frame for cracks near steering head
☐Verify hours on engine if meter present
☐Cold start test, should fire quickly
☐Inspect sprockets and chain for wear
Reliable if maintained, neglect kills them fast