Chris-PA
Where the Wild Things Are
I'm not sure why I keep fixing this thing. It has so many design flaws, most of which stem from the too-small crankshaft counterweights and the vibration they cause, combined with a lack of locking hardware and weak A/V spring system. There are not too many parts of it that haven't been rebuilt, often many times, and ultimately modified or redesigned.
Still, it makes a nice light saw for felling stuff that's in it's range. This last time it ate a choke plate screw that some idiot forgot to LocTite in. The cylinder was mostly unharmed, but the piston was toast and the lower cap got cracked and broken out. It went in a bin for many months, as I'm just not that interested in working on chainsaws anymore, but eventually I missed my light 20" saw and ordered a piston kit and some new crank seals.
This saw was the first one I ported, and the timing is kinda dumb. It's got too much intake duration, although the intake width is only about 55% of the bore, and it's very rounded at the bottom due to the location of the impulse port (not really a bad thing). The exhaust port was only about 53%, so I widened it out to 60% to try to balance the intake. The squish is a bit large at 0.040", and there is too much case volume for it to ever rev well.
So I rebuilt it carefully, with new piston, new pin and bearing, and new seals. The bored-out carb got a new diaphragm, everything got cleaned and gone over, and I filed the nearly-new chain just to be sure. I got it together and let the sealant set over night, and I tried it out when I got home from work.
It ran like crap - I could not get it tuned, it stalled all the time, and it cut in a big nasty arc that made the bar/chain wedge in the cut. I took it back to the shop to try to see what was up, and it would not start at all. I could see there was fuel in the line but the plug was dry even on choke. I threw it in the barn and said to hell with it.
Yesterday it got a new fuel line and the chain got filed again (I had brushed something and the sideplates of the outside cutters were trashed). And now it's back! I dropped an ash, and it ran well and never stalled. It's no speed demon, but for a 46cc saw with a 20" bar it is competent, and it's light and well balanced.
This is hard white ash, and TriLink full chisel chain. It's turning 9.7-10k and chugging through pretty well, which isn't too bad for 46cc:
Still, it makes a nice light saw for felling stuff that's in it's range. This last time it ate a choke plate screw that some idiot forgot to LocTite in. The cylinder was mostly unharmed, but the piston was toast and the lower cap got cracked and broken out. It went in a bin for many months, as I'm just not that interested in working on chainsaws anymore, but eventually I missed my light 20" saw and ordered a piston kit and some new crank seals.
This saw was the first one I ported, and the timing is kinda dumb. It's got too much intake duration, although the intake width is only about 55% of the bore, and it's very rounded at the bottom due to the location of the impulse port (not really a bad thing). The exhaust port was only about 53%, so I widened it out to 60% to try to balance the intake. The squish is a bit large at 0.040", and there is too much case volume for it to ever rev well.
So I rebuilt it carefully, with new piston, new pin and bearing, and new seals. The bored-out carb got a new diaphragm, everything got cleaned and gone over, and I filed the nearly-new chain just to be sure. I got it together and let the sealant set over night, and I tried it out when I got home from work.
It ran like crap - I could not get it tuned, it stalled all the time, and it cut in a big nasty arc that made the bar/chain wedge in the cut. I took it back to the shop to try to see what was up, and it would not start at all. I could see there was fuel in the line but the plug was dry even on choke. I threw it in the barn and said to hell with it.
Yesterday it got a new fuel line and the chain got filed again (I had brushed something and the sideplates of the outside cutters were trashed). And now it's back! I dropped an ash, and it ran well and never stalled. It's no speed demon, but for a 46cc saw with a 20" bar it is competent, and it's light and well balanced.
This is hard white ash, and TriLink full chisel chain. It's turning 9.7-10k and chugging through pretty well, which isn't too bad for 46cc:
