045 Super Up and Running, Thanks ArboristSite!

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I'd like to thank many of you on this forum for helping me get this saw overhauled. @hotshot, @atpchas , and @Coralillo Lo Pro provided guidance on specific questions, and I'd read a lot of old posts from the last 20 years that helped me on this project.

I'd been wanting a saw that can pull a 36" bar on occasion, and I had a chance at this 045 AVSE from a friend. It was running well, but would die when hot after a couple long milling passes. The prior owner had it for a long time (30+ years), and used it for firewood and recently milling. It was getting hard for him to operate; it's no lightweight and there's no compression release.

I knew it needed a new ignition, but I tore it apart to see what else it might need. I'll go through each major component below.
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Cylinder

The original cylinder was in good condition. It appears the saw had always been run with plenty of oil. There were no air leaks when I tore the saw apart. There was some aluminum transfer from the piston, but it cleaned up easily with an ultrasonic cleaner and emory cloth. The ports and chamfering were very clean, except for some minor imperfections/burr at the bottom of the intake port.

The factory numbers on this saw were:
Squish: .045
Exhaust: 106
Intake: 72
Transfers: 128

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Piston
The original piston did not show any damage, and the rings were free, but it had worn down to 2.117" at the skirt. I ordered a replacement piston from Proline. The Proline piston is lighter, and has windows unlike the original. There was a casting defect in the first Proline piston I received, but Gus at Sawzilla sent me a replacement as soon as I notified them. The dimensions of the new piston were slightly different than the original so I wound up with the exact same squish and port timing numbers with a Proline Piston and deleted base gasket. I used 54mmx1.5mm Caber rings with the Proline piston.

Base gasket delete, Proline piston
Squish: .045
Exhaust: 106
Intake: 72
Transfers: 128
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Cylinder Work

I took .020" off the base of the cylinder to get squish to .025". This brought my exhaust to ~107 and intake to 75. My intent was just to polish the exhaust and remove the burr from the intake floor. Removing the bur on the intake resulted in an additional 2 degrees of intake timing, and I accidentally raised the exhaust more than I intended. The exhaust port leaves this cylinder at a steep downward angle, which makes the shape of the exhaust roof deceiving. I thought it was domed after I polished it, but I inserted the old piston and realized that I had flattened the roof excessively. I added some dome back to it, which increased my exhaust duration a little more than I intended at the first whack.

Base Gasket Delete, Proline Piston, .020" off deck, porting:
Squish: .025"
Exhaust: 104.5
Intake: 77
Transfers: 131

 

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Muffler

If you look at the pictures below, the muffler had 6 holes in the middle portion when I got it. Not sure if they came that way from the factory, or if someone had drilled them out in the past. I cut out the space between the top 4 holes to provide a bigger exhaust outlet, we'll see if I feel the need to remove more in the future. I painted them with flat black header paint.
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IGNITION

The saw came with a SEM GE ignition, which was giving up. I was going to try to fix that ignition per the German YouTube video, but realized with some help from the forum that I'd also need a new flywheel. I ended up buying a Bosch ignition assembly and flywheel from a forum member. The Bosch is working well for now, and I hope to repair it with a Universal Ignition Module (located in a cooler location) when it fails.

IGNITION TIMING
I rotated the stator plate clockwise so that the washers on the screws were almost to the edge of the holes in the plate before tightening. When I reassembled and checked with a timing light, this yielded

24-25 degrees BTDC at idle
29-30 degrees BTDC above 5,000 rpm

It is still starting and idling well, would you guys mess with the timing?

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I rebuilt the carb, replaced some seals and hoses, and it is running great! I have not given it a real workout yet, I'll let you know what I think once I do. I'll probably run a 7 pin rim sprocket with longer bars, but I might also try an 8 for fun. It came with a metal screen air filter, and I might want to come up with a replacement for that. Loggers here used to remove the carb cover and run a foam filter on these 045s and 056s, I might try that. I don't like having a filter exposed to the elements, but I think the factory one will clog quickly. Guess I'll try it first and see.

Thanks again for the resources and information you guys provide. Have a good one!