Chainsaw Repair

In the 80's I worked for a Stihl and Poulan dealer,we sold a lot of saws,a few fallers bought the 5400,and they were quite reliable with no real problems and the reed valve motor had good power,and they were really smooth,less vibration. One quirk they had was idling,because of the reed design and the angle the port entered the crankcase they tended to "load up" with fuel and idle quickly got richer if asked to idle for very long,the engine could slow down and stall. The only cure for this I found was to set the low speed mixture as lean as possible but so it could still accelerate without a bog,that works best.
Some different brand bars were often a sloppy fit on the barstuds,you could move the bar too much up and down.
There is one thing I learned you must be very careful of on these saws,removing and re-installing the clutch to maybe replace the rim sprocket,you must try to tighten the clutch back on as well as you can,but NEVER test run the saw after without the bar and chain on,or you will have grenade blow up in your face at 10,000 rpm! After installing the clutch you need to put the bar and chain on and do a good hard cut in some wood to tighten the clutch on completely. If you try running the saw after installing the clutch with no bar and chain on the clutch will not be on tight enough,as usual you will start it, blip the throttle a few times,and then rev 'er up to hear it rev cleanly,but when you back off the trigger... to your horror you will suddenly see the clutch unscrewing and coming off the the end of crankshaft,get your face outa the way quick and hit the deck because when the clutch comes off at high rpms if flies apart instantly with tremendous force,one time I could not find any of the clutch parts after,they flew too far and were gone,but later that day an old guy came to the shop with all the clutch parts in his hands,found them scattered on his lawn 2 houses away. It happened to me several times.
They are great saws with few faults. One day Poulan shipped us the new 8500's, they looked better,the cast starter cover and rewind cover were replaced with more modern light weight ones and the saw looked more modern and was lighter.  We quickly sold 2 of them but they were soon to haunt me,the top covers and starter covers would not stay on,they fell off,the screws broke,they wore deeply into the crankcases and one crankcase broke soon, I think they needed some heftier better quality screws,but both saws were soon so damaged they were unfixable so we stopped selling them,what a shame because the 5400 was so reliable. I suppose maybe Poulan rectified the problem but we didn't risk selling another,we took a loss on the 2 we did. I imagine they were remedied and and were loved by their owners but I have no further experience with the 8500.
Poulan sent us a couple of performance reed valve kits for the 5400.
I made a hotsaw from a 5400 and it ran very well and was reliable.