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
โCheck frame for cracks near steering head
โVerify hours on engine if meter present
โCold start test, should fire quickly
โInspect sprockets and chain for wear
Reliable if maintained, neglect kills them fast