What causes Seized or worn power valve on the Yamaha Dt125r?

Rev through full range, listen for flat midrange power Estimated fix cost: $50-$150

What causes Worn or air-leaking crankshaft seals on the Yamaha Dt125r?

Erratic idle, hard starting, excessive smoke on startup Estimated fix cost: $80-$200

Hesitation, poor idle, fuel petcock and filter condition Estimated fix cost: $20-$60

Clunking over bumps, grab swingarm and check for play Estimated fix cost: $30-$80

Known issues to inspect before buying a used Yamaha Dt125r. What to check and how much repairs cost.

SERIOUS

Rev through full range, listen for flat midrange power

Fix cost: $50-$150

SERIOUS

Erratic idle, hard starting, excessive smoke on startup

Fix cost: $80-$200

MODERATE

Hesitation, poor idle, fuel petcock and filter condition

Fix cost: $20-$60

MINOR

Clunking over bumps, grab swingarm and check for play

Fix cost: $30-$80

☐Check for fresh oil leaks around engine cases

☐Test ride through full RPM range hard

☐Inspect exhaust pipe for cracks or rewelds

☐Verify frame and swingarm are straight, not bent

Solid if maintained, neglect kills them fast