Poulan-related bar and chain swap question

[mexicanyella]

I've been reading a lot about bars and chains here on AS and am slowly absorbing info about different mounts, cutter types, gauges etc. I was looking at a A041-mount bar off a Poulan 2150 and a K041-mount bar off a Poulan Pro PP4620avx and just because it amuses me to mix and match things, I put the chainless 20" K041 bar on a 2150 powerhead and put the cover and nuts on finger tight. Made that 20" bar look pretty big...but it got me wondering...given the added top-to-bottom "height" of the 4620's bar, and its wider nose radius, what would the effect be of running a shorter version of that bar on a saw originally equipped with a skinny little A041 bar with the small-radius safety nose? Would the gentler nose radius require less power from the engine, all other things being equal?

Next question that occurred to me was, if you found a .325 drum/spur for a Wild Thing-family Poulan and put on a a short K041 bar for .325--say, a 13" or 15" one, like I've seen online, could the 42cc engine benefit from .325 chain if the bar was short enough, or would it just be better to stay with a 3/8 LP setup?

I'm tempted to try swapping the 4620's drum/spur onto a 2150 powerhead I have and try it with this 20" bar and chain off the 4620...if for no other reason than to see how quickly it bogs down with the added load. Thoughts?

 

[Franny K]

The a tail is A continuation of the K tail at least in the profile. It is not like they draw it in the literature. A k tail spaced somewhere around 1/4 to 3/8 inch farther from the sprocket will be the same but with a larger void. The 13 and 15 inch (0.325 chain) called length bars can be sloppy about calling an A a K. My guess is the a is for 6 tooth in 3/8lp, 8 maybe 9 in 1/4, and maybe 7 in .325. If you like modifying things a 3005 stihl bar at least a current one can be made to work with some slot lengthening and hole making, they take a somewhat different approach getting wider at the tail much quicker.


0.325 Nk (narrow kerf like oregon 95) has cutters only a tiny bit bigger than common 3/8 lp with bigger drive links. It should have resistance to de railing if no other advantages. You will be pulling one more tooth across a given spot every two revolutions.