This should be entertaining.
Tim Ard on ported saws.
- Thread starter bwalker
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Good video to review from time-to-time. It’s easy to get all wound-up modding saws and 2-cycle engines. Hell, what better topic to discuss here on AS than modding? Ask 10 opinions and get 20 answers.
JQ
JQ
You forgot to mention folks sent to "banned camp" for awhile.
Most of the things Tim mentioned are BS IMO
I'm sure some of factory chain saw motor design takes emissions into account and that mods can undo some of that design.
Does that leave the operator exposed to more emissions?
I bet it does.
As far as operator exposure goes running saws pig rich like many people do leads to much more exposure.
A modern compensating carb, strato charged saw is pretty clean when ported.
You don't think that more of the purging charge makes it out the exhaust port of a modded saw?
Seems that it would.
I run 40/1 in my Stihls and I'm pretty sure that it increases emissions.
On a strato saw no. On a regular two stroke it all depends on the blow down.
Running 40:1 vs 50:1 might increase emmissions by an extremely small amount. Carb settings have way more influence.
This one could turn into an oil thread I am going out to mix a can of gas for bucking fire wood tomorrow and I am keeping my mix ratio a secret.So there.
Kash
Kash
I've got a Stihl 362mc and was wonder about emissions. It seems really clean and a low user of fuel for the amount of cutting done.
I know it's drifting off topic but what is your opinion of M-Tronic?
I've also got a 241CM and it runs like a top.
They seem to rev high to me, I hope that they aren't running lean.
fixinsince69
ArboristSite Lurker
Great video, I worked for Hampton Equipment back in the 70's, Located in Lancaster NH and which was Stihl Distributor for Me,NH,and VT. I attended a training at Virginia Beach and Roger was our instructor. He was a great instructor. I was the go to mechanic for our dealer network and was in direct contact with Roger when I got stumped. He also had an assistant, his name was Ben if I remember correctly.
Mtronic/autotune are a great thing for most users.
The longer the blowdown duration before the transfers crack will no doubt increase emissions , regardless of ratio's , unless there is sufficient backpressure within the exhaust port & muffler which usually is not the case with a ported & muffler modded saw . Its all about timing the combustion gas's in the combustion chamber against the back pressure of the exhaust gases exiting the exhaust port , there is a point of equilibrium before the top transfer & exhaust port are completely open . Longer blowdown duration saws are much more effective with higher compression saws usually due to inherently bigger pistons & combined longer stroke . Anyhow emmissions are really not something a ported saw owner loses sleep over ! lol.
Borderline lean Del , " it's the nature of the beast " , richen up your oil ratio a tad perhaps or have your saw reflashed if you plug coloration is repeatibly too light !
Strato engines run really lean when cold starting also. It's just the nature of the beast.
Compensates.
Yeah , the Stihl M & Husky Auto tune pretty well compensate for the reduced back pressure and overall lower operating temps that modifications produce . Many of the 1st generation Stihl M had your lean condition , nothing real serious unless you really worked the saw hard , sometimes hot restarts posed more of headache . A friend had to have his brought to the dealer on warranty for this very condition . It now runs properly . If you have the app you could do it yourself lol.
