Remembering for a moment that there are some of us who don't have a fraction of the saw maintenance expereince that many here have-and even some of us who have never broken down a saw beyond changing the filters and replacing a sprocket. With that as background info, just how complicated would it be to switch out the P&C on a 6401. Presumably there is a single connecting rod (bearing and race assembly) that attaches to the crankshaft in a similar fashion to an auto engine except obviously there is only one piston. What are the potential trouble spots of this procedure.
Thanks in advance for all constructive advice.
Hugenpoet
Hi Hugenpoet, To answer your Question about top end swap on a PS7900.
First remove air filter and cylinder covers, air cleaner and blow all debris from top of the saw especially around the cylinder base., Then Remove the muffler and carburetor with your T-27 torx and clean some more, then remove the 4 bolts that hold the cylinder down again with your T-27 torx. unbolt the AV mount from the cylinder and carefully lift the cylinder off the piston. with a small pair of needle nose pliers remove the circlip form the piston and carefully push the piston pin out of the piston. inspect and reoil the wrist pin bearing. carefully remove any gasket material that stayed attached to the crankcase. Now install the new piston to the rod with the arrow pointing tward the exhaust. Install the new cylinder base gasket on top of the crankcase and compress the ring with a suitable type ring compressor oil the bore of the new clean cylinder and carefully push the cylinder down over the piston. line up the holes and bolt the cylinder down and tighten. I forgot to mention to swap the carb intake boot when the cylinders are off in your hands this can be done on the saw but is easier to do while the jug id unattached. Now reinstall the muffler, av mount and carb and filter and hoods richen the carb adjustments a tad and start. It will smoke initially due to the lube you wiped inside of the cylinder wait for the smoke to clear check the running and acceleration of the saw and go cut some wood and have fun.
If your not comfortable with this job I charge approx. a half hour labor + shipping to do this for you.
Scott