Had the same jaws pipes on my ptek 860, just couldn’t get them to work at elevation as good as my dynoport does. Now those jaws pipes just collect dust in a box.
Why don’t you give a call to dean at mad motors or Brent at Arctic edge, they may have a crank and recommend what pistons to use. My experiences I’d stay away from rkt, and wiseco are fine if you warm up properly.
Both are really good machines, but I would get rid of the carbide runners and get some hard steal ones to save your front end also some venting for that under hood heat and keep them clutches cool.
It’s more piece of mind when to do it. I got a ptek that when over 12,000kms before it needed a top end and I’ve seen some that didn’t even make 2000. Id do a compression and engine fitness test also check your crank runout first.
2.5 is pretty much max you can stuff in there on stock drivers even at that it will rub some rivets till it breaks in, 3” if you go 7t drivers or drop and roll your chaincase.
That’s pretty normal, I always put in a little bit of oil on top of the air side of the piston on all my rebuilds. Just don’t every compress the shock with out any reasonable psi in the air chamber.
Had something similar years ago but with a primary on my old Yamaha. Not even 8 rides on the brand new clutch before it blew apart, also took out my secondary, side panel, hood, and foot well. Lucky I wore steel toes boots at the time. Turned out the primary was badly casted.