James:
Is the spark that you are seeing inside the rear vent only really noticable when you relase the trigger, or is it a constant sparking? If you only really notice it when you relase the trigger it is the brake mechanisim stopping the rotation, and very normal. I have to 14.4 xrp's, one old, one new & they have both done that as long as i've owned them. They are tough as nails, you can put them through hell and they'll still go...i've literally had mine smoking on more than one occasion.....I've found the main issue with the xrp models is over time, the chuck will wear out before anything else....
ryan, August 2008
