I can’t thank you enough sir! I’ve been toying a used pile of these saws for months now trying to create a “good running” little monster. I just built it your was with crank case match and piston cut outs and man it starts up great. I’ll be running it today!
Oh wow! my thought was they used the lower walls with the crazy notches to meter the velocities into the cylinder individually to each port for a combustion swirl while maintaining economy. Going to be interesting to see the chain speed and torc you develop with that. Awesome series!
Thanks for the tutorial!!! Just did a cheapo china tophandle, runs like hell now, without muffler. Enlarged exhaust width, about 80% more area, square with round corners now, didn't change much in timing. Little work on the inlet, lowered it a little, maybe 0.5mm and made it more square, is more like round originally Care must be taken there, because of the impulse tube below, don't connect it to the inlet. And the piston, big soft (maybe 30°) ramp where the transfers are. Transfers are open, not integrated into the piston, like here. Much cheaper to learn on cheap chinas than to mutilate one of my Solo681s with a bad porting job.
Oh, you just answered my question about how you raise the upper transfers on a 4910 without a 90 degree hand piece. You do have a dental set, and that is how you get it done. I learn so much from your channel, so thanks! I don't have a lathe, and just do base gasket delete on some saws, but that also drops the upper transfers a little. I haven't messed with them. But, maybe I can get one of those dental 90 degree hand tools for not too much money. The real ones are like 400 bucks, and I'm just goofing around, and don't have that much extra money to goof with.
So to be clear you are running a gasket on that? It's cool hearing you mention you'd gotten away with straight-bits only, am on the fence Re opening mine because I figured I couldn't do any legitimate opening to the transfer loop (just some opening/flowing & case-matching of the bases of the lower-transfers like on my 590) and cannot sand the base to drop a winged cylinder-base like this (or the 590...but could go gasketless there, wasn't sure if you could here) Very nice hearing you say guys get by w/o gaskets, any anecdotes of someone's attempt *not* working despite a good layer of Moto/etc? I ask because from my point of view, having a unit that's already got timing advanced & the exhaust-flange, through the entire muffler/exhaust system, fully ported/flowed, I have to imagine my unit would benefit from simply dropping the base (powerstroke & swept-volume increase which, normally, would start testing the limits of OEM blowdown-window, especially if timing is advanced, but the opening of the exhaust system, and a flaring of the exhaust port's entry & widening of the port, should allow quicker/more efficient blowdown and "let you get away" more optimally with higher compression, further-advanced timing & slightly higher pressure during powerstroke w/o sacrificing any RPM's if you ported the center-ceiling of the roof to OEM ceiling-height after dropping it, what, ~15thou?) Re the fuel-econ of these units, no way are they bad / "normal", I can take one up and do an average Live Oak canopy with 1-2 tanks depending how spready its crown is, Live Oak is our predominate specie but is also one of the hardest cuts I know, anyway was *astounded* how long the OEM unit took to idle-through its 1st two tanks of gas(didn't bring it to throttling til tank 3 and my store was cool enough to only idle it before letting me take it), figured I'd lose that once I opened the exhaust system a bit (I did *not* go and gut the muff like so many, merely optimized it, it's not spewing charge :P ) and advacned timing but honestly the loss seems
I can’t thank you enough sir! I’ve been toying a used pile of these saws for months now trying to create a “good running” little monster. I just built it your was with crank case match and piston cut outs and man it starts up great. I’ll be running it today!
Oh wow! my thought was they used the lower walls with the crazy notches to meter the velocities into the cylinder individually to each port for a combustion swirl while maintaining economy. Going to be interesting to see the chain speed and torc you develop with that. Awesome series!
I love how simple it is to get those motors out. Minutes and a few screws it slides right out.
Awesome work guys!!!
🤝🤝🤝
Thanks for the tutorial!!!
Just did a cheapo china tophandle, runs like hell now, without muffler.
Enlarged exhaust width, about 80% more area, square with round corners now, didn't change much in timing.
Little work on the inlet, lowered it a little, maybe 0.5mm and made it more square, is more like round originally
Care must be taken there, because of the impulse tube below, don't connect it to the inlet.
And the piston, big soft (maybe 30°) ramp where the transfers are.
Transfers are open, not integrated into the piston, like here.
Much cheaper to learn on cheap chinas than to mutilate one of my Solo681s with a bad porting job.
Sweet, I'm the 1000 sub. Can't wait to see the content.
Looks great! 1/4 pitch is almost mandatory for these. It’s be cool to see her run
Looks good,I like the removable cyl on a clam shell.
It's not a clam shell has its own crank case cilinder comes off like a normal mag case saw
Gonna be a little beast! 👍👍👍👍🇺🇸🇺🇸🇺🇸🇺🇸🙏🙏🙏🙏
Oh, you just answered my question about how you raise the upper transfers on a 4910 without a 90 degree hand piece. You do have a dental set, and that is how you get it done. I learn so much from your channel, so thanks! I don't have a lathe, and just do base gasket delete on some saws, but that also drops the upper transfers a little. I haven't messed with them. But, maybe I can get one of those dental 90 degree hand tools for not too much money. The real ones are like 400 bucks, and I'm just goofing around, and don't have that much extra money to goof with.
Lot of differnt ways to do it depends on the model saw
So to be clear you are running a gasket on that? It's cool hearing you mention you'd gotten away with straight-bits only, am on the fence Re opening mine because I figured I couldn't do any legitimate opening to the transfer loop (just some opening/flowing & case-matching of the bases of the lower-transfers like on my 590) and cannot sand the base to drop a winged cylinder-base like this (or the 590...but could go gasketless there, wasn't sure if you could here) Very nice hearing you say guys get by w/o gaskets, any anecdotes of someone's attempt *not* working despite a good layer of Moto/etc? I ask because from my point of view, having a unit that's already got timing advanced & the exhaust-flange, through the entire muffler/exhaust system, fully ported/flowed, I have to imagine my unit would benefit from simply dropping the base (powerstroke & swept-volume increase which, normally, would start testing the limits of OEM blowdown-window, especially if timing is advanced, but the opening of the exhaust system, and a flaring of the exhaust port's entry & widening of the port, should allow quicker/more efficient blowdown and "let you get away" more optimally with higher compression, further-advanced timing & slightly higher pressure during powerstroke w/o sacrificing any RPM's if you ported the center-ceiling of the roof to OEM ceiling-height after dropping it, what, ~15thou?)
Re the fuel-econ of these units, no way are they bad / "normal", I can take one up and do an average Live Oak canopy with 1-2 tanks depending how spready its crown is, Live Oak is our predominate specie but is also one of the hardest cuts I know, anyway was *astounded* how long the OEM unit took to idle-through its 1st two tanks of gas(didn't bring it to throttling til tank 3 and my store was cool enough to only idle it before letting me take it), figured I'd lose that once I opened the exhaust system a bit (I did *not* go and gut the muff like so many, merely optimized it, it's not spewing charge :P ) and advacned timing but honestly the loss seems
Cant wait to see what it will do
I wondered if you could get your tools inside that cylinder. You've got some nice small grinders but this thing is tiny.
That's one tiny cylinder
Cut a branch and filler up 🤣🤣👌
Where you get the 1/4" setup?
Monkeybeaver.com
So how did the porting end up affecting the fuel economy on that little booger
It's not bad I can get a lot cut up with it before filling it
Used these tips now mine rips!
👍