Chainsaw Repair

I always admired the 85cc 5200, 5400 and 8500 Poulans from the past.  My brother raced a couple with pipes back in the day. Also 7 time Hayward world champ Ron Hartill and his son Dale raced really fast ones.
 Back in 1975 when the 5200 was introduced I can't think of another saw at the time that could beat it's power to weight ratio and ergonomics.

Here's the best video I could find of a 5200, as this guy could handle it pretty good and also not screw up the chain with bad hand filing.
Appears the slow idle down time after the cut may require an upgrade to the reed valve or maybe crank seals, ran strong in that big hardwood though.
 
Very nice video.....anyone know who he is? And also what upgrades were from the 5200 of 1975 to the 8500 of 1984?

My Craftsman 5.2/30 (Red Sears badged 5200) and Poulan 8500 are two of my favorite saws. 

I agree that his saw sounds like it may have a leaking crank seal.  Probably the FW side, as when the PTO side seal leaks on these they usually smoke a bit as that seal has the wet side of the auto oiler pump over it.  My 4900 ran great when I first got it, but smoked and was a bit slow to return to idle.  Both symptoms went away when I replaced the crank seals.

530019075 is the Poulan # for the seals.

SKF 6904 and National/Timken 471466 are numbers you can use to get seals from bearing houses and auto parts outlets.

Very nice video.....anyone know who he is?

He is a member here and from Ohio.   Just be careful dealing with. Have heard GOOD and BAD.

I couldn't list them all but the motors stayed pretty much the same. Bar studs were changed from 5/16 to 3/8, the 5400's added a hand guard to the rear handle.
The starters were upgraded for durability and 10-24 fasteners for the starter housing to case were changed to 1/4 - 20. At some point early on a rib was added to the front of the case for durability and the top cover fastening was changed from a captive nut with locating pins to three screws. That was likely for a cost savings. The starter housing was changed, I believe by adding a stud to anchor the recoil spring.
The 8500 had a different air filter system.

The power stayed the same as I guess that was very difficult to improve on.
I couldn't agree more as to how powerful and innovative these saws were when they were introduced.

Looking forward to pics.  The 6900/7700/8500 has a plastic top cover with separate af cover to go with the different af that Tim mentioned. 

The 4400/4900/5400 and later saws have a longer tank/rear handle casting.  More fuel capacity (and distance between the handlebar and rear handle.............and more weight). 

The plug lead is different on the coil of the 6900/7700/8500 saws. 

The 6900/7700/8500 saw cylinders have a different fin profile than the 1st and 2nd gen saw cylinders.  The bulkhead behind the jug is different to match. 

The 6900/7700/8500 saws have a larger crank PTO snout, with a larger clutch bearing and race and a different clutch drum and hub.

Tim covered the remaining upgrades.  The 3/8 bar studs were phased in during the 4400/4900/5400 production.  There were 2nd gen saws with both stud sizes.  My 4900 had 5/16" studs.