So I'm about to do a service on the bike and the service manual says to replace the fuel hoses and brake lines every 4 years. No idea when they last got replaced. Would you recommend replacing them or if they look fine then leave them?
condition of lines is more often determined by weather and sun exposure than by age. check all lines for cracks or weathering, and go from there. unless it sat out all year it should be fine, dont fix what aint broken. if you do a tank or carb removal, you will see how hard or pliable the fuel lines are and can change them then.
Fuel lines on mine are 24 years old and perfectly serviceable but they do get a rub over with silicon grease now and again.
I wouldn't chance the brake lines though, especially the rear. :D
I think Suzuki say 4 years For liability reasons more than anything else.
Pretty sure I've seen fuel lines out live the later year petcocks....