I was kinda looking forward to running that thing in factory form on Saturday, but somehow I knew it wouldn't make it more than a couple day's without being molested.
Too late now:hmm3grin2orange:
The MS261 is here!!
- Thread starter blsnelling
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Too late now:hmm3grin2orange:
Erick
Addicted to ArboristSite
Should respond well, in true Stihl fashion it looks like a scaled down 441.
sjp
ArboristSite Operative
Great job!!!! Great info!!!!!! Keep it comeing
logbutcher
Addicted to ArboristSite
Tzed250
Addicted to ArboristSite
2000ssm6
Stihl User
Brad, what do you think of the p&c's quality?
StihlyinEly
Addicted to ArboristSite
I was curious about this as well. So much is made of the Mahle that I wondered how the Stihl stacks up.
The P&C look very nice. Ports are very nice, as well as the beveling. The only minor nit pick is sand casting roughness on the sides of the exhaust port. That's all been ground away though.
I've always tried to be very up front and honest, giving you guys both the good and the bad. Well...my first go around at the porting was a huge disappointment. I litterally only got a 2% gain
At least it didn't go backwards, lol. I've got it back apart and am making some pretty radical changes. I'll be back soon:chainsawguy:
At least it didn't go backwards, lol. I've got it back apart and am making some pretty radical changes. I'll be back soon:chainsawguy:
Killed the thread did I, lol?
The first time in I raised the exhaust to 102° in an effort to get a couple more degrees of blowdown. I lowered the intake to 80°. I widened the transfers towards the intake, and widened the intake and exhaust to skirt max. I also widened the strato "transfers" forward. This is what only have a gain of 2%.
So, I went back in. I was originally shooting for 100° on the exhaust, so raised that a couple more degrees. That gives me blowdown of 22°. The big change was that I leveled the transfer ports, such that they all open at 122°. I'm now up to a measely 4.5% improvement.
Somewhere in this saw is a bottle neck. I removed the filter, and that made no change at all. I'm thinking it's those tiny transfer ducts, or the carb itself.
I do have one more idea to try.
BTW, I'm still running the original 7-pin rim. This saw has pleny of grunt to pull an 8-pin, but I'm trying to keep it a level playing field at this point.
The first time in I raised the exhaust to 102° in an effort to get a couple more degrees of blowdown. I lowered the intake to 80°. I widened the transfers towards the intake, and widened the intake and exhaust to skirt max. I also widened the strato "transfers" forward. This is what only have a gain of 2%.
So, I went back in. I was originally shooting for 100° on the exhaust, so raised that a couple more degrees. That gives me blowdown of 22°. The big change was that I leveled the transfer ports, such that they all open at 122°. I'm now up to a measely 4.5% improvement.
Somewhere in this saw is a bottle neck. I removed the filter, and that made no change at all. I'm thinking it's those tiny transfer ducts, or the carb itself.
I do have one more idea to try.
BTW, I'm still running the original 7-pin rim. This saw has pleny of grunt to pull an 8-pin, but I'm trying to keep it a level playing field at this point.
2000ssm6
Stihl User
No thread killer. Most don't know how to take you tearing apart a new saw.
They will get used to it. I'm following, I'm going to put a few more tanks through mine before it gets shipped off though.:biggrinbounce2:
2000ssm6
Stihl User
I don't understand the need for the split from the intake into the cylinder. I could if the carb was a 2 barrel like other strats. Have I missed something in the pictures?
2000ssm6
Stihl User
That would suck if it needed a different carb to run right when ported. I can live with a muff mod though.
Zombiechopper
Addicted to ArboristSite
remove the partition and let all the ports get fuel?
2000ssm6
Stihl User
I like this idea but that split has to serve an important purpose. Maybe that is part of an EPA feature to enable it to run cleaner?
sunfish
Fish Head
No, you just scared everybody with the 2%, lol.
No, you just scared everybody with the 2%, lol.
Or at least made 2K start drinking heavily. :hmm3grin2orange:
It is for pollution control. Basically it splits air fuel mixture and air mixture to different ports for scavenging leading to a cleaner running engine.
I still prefer the non-strato engines, but this is the wave of the future due to mandates by the EPA
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