The Kelty PK50 is a 3175 cu in (52 L) pack that weighs 51 oz (1450 g) in size M/L. I like the main compartment and front stash-it pocket, but wish the hipbelt pockets were bigger. The hipbelt padding and shoulder straps are quite comfy, and together with the curved single stay and hourglass frame sheet, the pack carries pretty comfortably. However, it has an overabundance of pockets and straps - way too many for the ultralighter. So I decided to do some minor modifications and share my experience.
Net result: in about 20 minutes I was able to cut or remove about 13 oz for a new weight of 44 oz. I ended up with a much cleaner looking pack that probably has a volume of 35 to 40L - perfect for most overnight trips. With a sewing machine, I could drop another ounce or two pretty easily, maybe more. FYI - the drop page is here: https://www.massdrop.com/buy/kelty-pk50
On my scale, my pack weighed 56.8 oz. The rain cover (3.6 oz) and front pocket (6.5 oz) are both removable, making a savings of 10.1 oz - the first and easiest steps in dropping weight.
Next I took out the scissors to remove any superfluous stuff. First I cut out the "wing" pockets. I would have removed the entire wings, but the water bottle pockets and compression straps are basically integrated into the wings. I think there is a way to cut them away partially but that is a project for another day.
Next I cut the length of some of the straps, especially the front compression straps and the hipbelt straps. Too long? Cut it down!
Inside the pack, I cut out the hydration pocket (but left the strap at the top to hang a hydration reservoir) and the sleeping bag separator shelf and buckles. I removed some of the extra buckles (shown here - how to pry apart the buckles that are sewn into the pack).
I ended up with a 44 oz pack that is much simpler and cleaner looking.
If I spent a little more time on the sewing machine, I would:
Double-back the straps that I cut short, so they wouldn't slide through the buckles, and probably cut more of the straps shorter
Cut away the wings to just have straps and water bottle pockets, or sew the water bottle pockets to the main compartment
Sew shut the bottom access and cut off the extra fabric and roll closure system