Bull, there aren't as many saw afiocionados here as at AS....
Axman, these are aftermarket kits, sold by Bailey's. Each adds 6 or so cc's to an 044 and 46, respectively. price is $99. I have one of the older Bailey's kits for an 044, but it is not an overbore. I've heard, from ehp and others, that the quality is not quite up to the OEM product, which is made by Mahle, I think..not sure if that is the correct spelling.
What I mean is on the aftermarket jugs they donot leave much metal around the ports , they are very thin so doing a woodsmod is not a good deal , they are fine in stock form but some have pretty weird combustion chambers .
Now maybe Baileys have made a better jug with this new design, I havenot worked on one of their new big bore kits
How much more power? Is it worth $150 dollars? I live in Colorado and I mainly do work at 5,000 feet elevation. I am told by the Stihl dealer here in town that a chainsaw will loose 3 percent per every 1000 feet gained in elevation. /forum/images/graemlins/trulies.gif That would leave me with a 15 percent loss of power. I don't know if he is correct on that. Anyway, could I get that power back if I got one?
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I live in Colorado and I mainly do work at 5,000 feet elevation. I am told by the Stihl dealer here in town that a chainsaw will loose 3 percent per every 1000 feet gained in elevation.
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I remember living in both Colorado and Arizona at >7,000' elevation each, and that my motorcycles performed about the same there with me riding solo as they did at <1,000' elevation while carrying an additional adult. That's a significant difference to be sure, but I don't know how well it correlates to that 3%/1000' figure.
In any event, if you've got $150 and an hour or so to throw at your saw it would undoubtedly net a helpful improvement.
So I got one of these for my 460 the other day. Didn't really need it, just wanted to get a little more power. I polished and took out the little imperfections in the ports before I put it in. I haven't gotten a good chance to run it in big wood yet, but it seems to have a bit more power. I ran some numbers and this is what I figured out for the 046/460 kit:
Bore up 2MM to 54MM - Same as 660
Displacement goes up to 82.4 CC - Gain of 5.9 CC's, about 2.5 CC's less than 650
I'll have to get my saw laid into some big wood to be sure about how it runs, but it seems to be about as bog-free with an 8-tooth sprocket as it was with a 7-tooth. The compression seems to be about the same as stock, but I haven't checked it. I'll have to get back with more details.