02-03-2023, 10:59 AM
The factory procedure for simply changing the fork oil is to remove the innards. My guess: that this is the simply the fastest way to get all the old oil out. Professional mechanics don't have the time to spend 20 to 30 minutes pumping the fork leg to drain or refill the oil. I have never removed the innards of either leg because to remove the bolts holding them requires more force than I have the means or the courage to apply. I don't have a vice and any good way to hold the fork leg while applying that force.
Even if you do remove the damper, there is still the step after reinstalling it and pouring in the oil where the factory manual says "Repeatedly move piston rod (1) of the damper unit up and down. Air is expelled from the damper unit. Allow the oil to settle for a few minutes. Repeat the procedure until the oil is free of bubbles and the oil level no longer changes." In my experience it takes 30 minutes of constant pumping to "bleed" damper in this way. What professional tech has time for that? My guess is they leave the refilled fork sitting for half a day and hope it bleeds itself. Hence, fork oil change takes a whole day.
Even if you do remove the damper, there is still the step after reinstalling it and pouring in the oil where the factory manual says "Repeatedly move piston rod (1) of the damper unit up and down. Air is expelled from the damper unit. Allow the oil to settle for a few minutes. Repeat the procedure until the oil is free of bubbles and the oil level no longer changes." In my experience it takes 30 minutes of constant pumping to "bleed" damper in this way. What professional tech has time for that? My guess is they leave the refilled fork sitting for half a day and hope it bleeds itself. Hence, fork oil change takes a whole day.