What causes Rectifier/regulator failure causing battery drain on the Triumph Bonneville America?

Test charging voltage at idle and high RPM Estimated fix cost: $150-$300

What causes Fork seal leaks on older examples on the Triumph Bonneville America?

Look for oil residue on fork legs and dust seals Estimated fix cost: $100-$250

Inspect rubber diaphragms for cracks or pinholes Estimated fix cost: $50-$150

Known issues to inspect before buying a used Triumph Bonneville America. What to check and how much repairs cost.

SERIOUS

Test charging voltage at idle and high RPM

Fix cost: $150-$300

MODERATE

Look for oil residue on fork legs and dust seals

Fix cost: $100-$250

MODERATE

Inspect rubber diaphragms for cracks or pinholes

Fix cost: $50-$150

☐Check charging system voltage output

☐Inspect forks for oil weeping

☐Cold start test for carburetor health

☐Verify service history and valve clearances

Generally solid, electrical gremlins are main concern