What causes Carburetor clogging from ethanol fuel on the Qj Motor Sf450r?

Rough idle, hesitation, hard starting on test ride Estimated fix cost: $30-$80

What causes Chain and sprocket wear neglect on the Qj Motor Sf450r?

Inspect chain slack, look for hooked sprocket teeth Estimated fix cost: $60-$150

Check all lights, indicators, and ignition function Estimated fix cost: $10-$40

Oil residue on fork tubes below seals Estimated fix cost: $80-$160

Known issues to inspect before buying a used Qj Motor Sf450r. What to check and how much repairs cost.

MODERATE

Rough idle, hesitation, hard starting on test ride

Fix cost: $30-$80

MODERATE

Inspect chain slack, look for hooked sprocket teeth

Fix cost: $60-$150

MINOR

Check all lights, indicators, and ignition function

Fix cost: $10-$40

MODERATE

Oil residue on fork tubes below seals

Fix cost: $80-$160

☐Cold start the engine yourself

☐Check frame welds for cracks

☐Confirm title is clean and clear

☐Test brakes front and rear firmly

Decent budget bike, maintenance history matters most