still a pain in the ass issue though lol i'm not convinced that inboard clutches have anything to do with it or that inboard clutches hold the sprocket out further on the crank. they are both aligned with the bar pad and regardless which side the clutch is on the sprocket is in about the same spot on the crank.
i totally agree with you on sprocket alignment. the problem with inboard clutches is that they are shrouded under the oil pump cover and wrapped around the pto bearing and seal. due to the closeness, heat transfer to the pto bearing could be via radiation, not just convection. an outboard clutch is hanging out in the turbulent pto side air, further from the case, bearings and seals. when it comes to radiant energy, distance is important. also significant is that the oil pump cover restricts air circulation around the clutch drum. i'm not saying anything is true or false, just raising issues that need to be considered.
regarding over-tight chains, which was raised earlier., i suspect you know how to adjust a chain. you probably check it in the morning while you're fueling and oiling. even if you started tight, it wouldn't be long before your chain had streatched, the sprockets and bar had worn and your chain was in the normal mode. do you keep your chain too tight?
But the fact is, inboard clutches might be proven and durable, but Husky don't make them (yet?). I won't argue that the technology isn't there to do it, but the point is that Husqvarna has only a single big engine saw with an inboard clutch, and that particular saw has bearing issues (specifically PTO bearing), and Husky themselves rate the max bar length on that saw 4" smaller than their own saw with an outboard clutch saw which is a whole class smaller (the 576At).
Again, people run a too long of a bar on the 390, and when limbing or in big wood it puts too much tension on the chain (as you noted) and it wears on a bearing not matched for that pressure.
So the point is, there's an issue with the bearings, and I'd imagine before Husqvarna releases a new 590 saw they'd want it sorted out and not be limited to a 28" bar on what would surely be a very powerful saw. Maybe they need to beef up the bearings to accommodate the outboard clutch. Maybe they need a different crank configuration. Maybe they just need a thorough redesign. Or maybe they need to steal some proven tech for Stihl.
the only 5 series saw i've had in pieces on my bench is the 575 and i don't know anything about larger prototypes of this strato design but... the design is unlike any other saw, with long, very slender transfers that snake up the outside of the cylinder casting. if anyone has a complete grasp of how the piston works. please post it. every time i think i have it figured out, i see something wrong in my thinking and suddenly i need a beer. it also seems to depend on a very small crankcase volume, tightened further by "stuffers." it probably needs to have main bearings with the smallest outside diameter possible to keep volume low. i suspect, but don't know, that it depends on shock wave propagation, like an expansion chamber for part of its mojo. the point being that a 90cc or 95cc version of the same design type is likely a difficult, time consuming and expensive exercise. i'd love to talk to the guy behind it. by the way, the 575 has become my favorite saw since i got one several years ago. before, i used a 272, 385 and 394, depending on the situation. now i mostly just take two 575's. another thing is if you start at dawn and break for lunch at 1100 you're going to use less than three tanks of mix, often only two.
I'm just saying that I think it's reaching to think the problem is with the inboard clutch. There are too many saws with inboard clutches that don't have this issue. Besides, both the crank and bearing should heat up at the same rate.
brad, i need to apologize for one thing. i didn't understand what you meant by "using a chain brake." now, i think you meant the guy who can't figure out why his saw is jammed and keeps revving it to get it going again... until you show him how to operate the chain brake. if that's the case you weren't too clear, but still, my bad. however, i'm pretty sure that westcoaster doesn't fall into that category.
i know of 7 more with spun mains and the guys chose to run them that way til they die.
