We may have a new over thinker on our hands, I've been knocked down a peg.
LOL! I swear I let it bother me for a loong time before finally asking this! It was my recent learning that my $135 amazon saw is actually a "zenoah g2500" clone, and seeing how popular the g2500 platform seems in asia/non-western areas, has had me looking at ownership because kept thinking "has to be 1 main company making jugs at 25.4cc displacement, why else would major companies copy it?" as I didn't know it had to be a bore//stroke function (did find something interesting though....my g2500 clone is actually an outstanding-quality unit,
unlike some of the other g2500 clones out there...when digging, I found that zenoah is actually
Husqvarna Group, got me wondering....since they get more market-share in the US by splitting to Husqvarna&Poulan-Pro, have to wonder if scheppach isn't their "european Poulan-Pro" as, surprisingly, Scheppach seems a real company yet their csp2540 is a high-quality clone....feels like my poulan pro 4218a ie far nicer than it should be for its price!)
Love when you reply because your avatar is probably the coolest on any forum (what's your compression at on that btw?? Would love to hear your setup if you have a sec, have seen so many going with the 1/4" pitch conversions and am still confused why echo is selling the 2511 to european markets w/ a 1/4" setup but then using 3/8LP for us :/)
As said above it’s just normal coincidence bore x stroke in milimeters.
As for ECHO i believe it’s the only major manufacturer left making nearly all pistons, cylinders, gears and other major engine parts in-house (unless, of course you take into account those cloners from China as manufacturers)
Could you "explain like I'm 5" this whole "bore v stroke" concept? I guess that, to an ignoramus like me, I'm thinking "you could have a 5' wide, 2" tall jug, or a 5" wide, 2' tall jug,
you would choose"....presumably, then, there's a "optimal efficiency ratio" of stroke-to-bore? Is this something that is fixed, or is it played with (like compression) by the engineers to improve saws?
Maybe it's some kinda industry insider joke. 25.4 cm is 1 in exactly. But 25.4cc is 1.55ci, hmmm.
I....I feel real dumb for not having put that together myself
I mean jeebus that is obvious (not that it's "why jugs are 25.4cc" but just noticing it's the 1=2.54 ratio
)
Could also be an epa type thing, like over/under that displacement is required to be quieter or less emissions.
That'd be a tough sell I think, if there's saws coming-in at all sorts of displacements then it's hard to fathom that 25.3cc, or 25.5cc, would be viewed differently (oh unless you mean "class cut-offs" or something, like "it's not an SUV it's a truck", like at 25.5cc there's a new class/regulations so they're skating-under it)
nah, the emission steps in other continents are at 20 then 50 cc.
20 is irrelevant anyway, yet 50 gives you a clear hint why nobody is making 49cc saws anymore
but rather choose 50.1 or 50.2 whichever bore x stroke is more convenient.
EPA in US use “banking” system so that’s even less cc related:
https://www.ecfr.gov/cgi-bin/text-i...&node=pt40.36.1054&rgn=div5#se40.36.1054_1103
Thanks a ton for the link it's precisely the type of thing I wanted to get familiar with (am still trying to understand just how manufacturers//epa meet, for instance with echo's 355t the muffler comes as a fully-open box with phillips-screws to remove the restricter-plate, it's as-if they'd set it up so you can remove 3 screws for the muff mod, or leave it on for EPA compliance....same for the 355's air-intake, if you lift its air-filter there is a plastic restricter plate behind it, removal of this & the muffler's restricter let it run stronger but, surely, less-efficiently)
[and Re the 50cc thing...you mean there's 'cut-offs', so if I wanted to make a saw that was 49cc I'd be better-off making it a 50cc because I'd then be 'past a cut-off' for a new class/new rules&standards? That seems like such a crude, random way of approaching regulation of these engines...though I guess that in and of itself shouldn't be a surprise!!]
Everything designed in the engine world, whether saws, bikes, cars, buses, planes, rockets, spaceships, et al is ultimately based upon it's power to weight ratio, and cost per unit horse power while the EPA piggy backs on all of it(except for Spaceships...for now...). Where these factors meet is where you see products. Everything meets at an intersection, whether we know it or not. A good example is your pillow gun - where comfort and danger meet.
How 'involved' is the EPA when it comes to chainsaws, though?? As I alluded to earlier in-post, plenty of saws seem to make it seem intentionally-modifiable (overriding EPA restrictions, essentially) but I guess the EPA would be OK so-long-as most people were using them as-sold(which is the case)
I ask about chainsaws/small engines because, in my experience w/ FDA (when I was managing a vitamin/supplement franchise), the vitamin world was almost-fully ignored by the FDA, they'd seldom intervene (hell even for pharmaceuticals, most would be shocked to know how infrequently a pharma lab gets any in-person FDA visits) So, for the EPA - tasked w/ "the environment" - engines are simply a sub-set, and motor-vehicles are the big deal in that sub-set....can't help but imagine that stihl/echo/etc's EPA-interactions are simply "this is the threshold to meet" and the left rest to the manufacturers (ie, allowing them to make machines where you can easily bypass EPA restrictions, not unlike how the FDA considers Oxycontin "abuse-proof" because they added some ingredient to make it slightly-harder for addicts to use it....can't help but seeing a parallel of a weak "safety&security theater" being the case here like it is w/ the FDA..)
