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Fabulous

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I guess it depends on the build. I’ve tried running 32:1 and unless I’m working the heck out of the saw it seems to accumulate more carbon than 50:1 - IT could be the fuel itself is causing this. While pricey, the canned motomix alkylate fuel has served me very well and I use it on my smaller (40-60cc) saws. Obviously running a 395xp on it will cost an arm and a leg so IF I have a lot of large bar work (up to 5gal) I will use pump gas and mix my own. After I’m done I’ll drain the remainder and fill 1/2 way with the motomix and run it for a few minutes to “flush” out the pump fuel. I’ve noticed FAR fewer issues doing it thus way especially if the saw is going to sit on the shelf for weeks or months until it’s next use
 
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RCBS

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I used to refer to 'heavy' oil as running 'rich'. An old dirtbike mechanic corrected me. Increased oil means less fuel. This is when I realized that you can adjust the tune of a 2T by the screws or by the amount of mix added to oil. He explained that certain bikes he tuned 'rich' with the jetting and allowed 40/50:1 mix ratios and others would tune better using oil to lean the fuel 20/32:1 while using larger jets. It's not just conjecture on his part either. Everyone around here knows he's the guy to take your bike to if you have a fueling issue needing sorted or you just want it to run as well as it can, in it's current state.
 

bwalker

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I guess it depends on the build. I’ve tried running 32:1 and unless I’m working the heck out of the saw it seems to accumulate more carbon than 50:1 - IT could be the fuel itself is causing this. While pricey, the canned motomix alkylate fuel has served me very well and I use it on my smaller (40-60cc) saws. Obviously running a 395xp on it will cost an arm and a leg so IF I have a lot of large bar work (up to 5gal) I will use pump gas and mix my own. After I’m done I’ll drain the remainder and fill 1/2 way with the motomix and run it for a few minutes to “flush” out the pump fuel. I’ve noticed FAR fewer issues doing it thus way especially if the saw is going to sit on the shelf for weeks or months until it’s next use
Tuning issue.
 

bwalker

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I used to refer to 'heavy' oil as running 'rich'. An old dirtbike mechanic corrected me. Increased oil means less fuel. This is when I realized that you can adjust the tune of a 2T by the screws or by the amount of mix added to oil. He explained that certain bikes he tuned 'rich' with the jetting and allowed 40/50:1 mix ratios and others would tune better using oil to lean the fuel 20/32:1 while using larger jets. It's not just conjecture on his part either. Everyone around here knows he's the guy to take your bike to if you have a fueling issue needing sorted or you just want it to run as well as it can, in it's current state.
The differance between 50:1 and 25:1 is less than one jet size in a bike. Temperature has a much greater effect.
 

bwalker

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Please elaborat
There isnt much to elaborate on. If you're tuned rich you will burn dirty. Also using a high viscosity, high temp oil doesn't help either.
 
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Fabulous

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If you’re tuned rich on the h,l circuits it’ll burn dirty whether you are at 50:1 or 32;1! A gallon at 50:1 is 130.6 oz total , at 32:1 you would have 132 oz total. If you were tuned correctly at 32:1 then switching to 50:1 will require a slight adjustment of the needles and vice versa. Ive noticed the motomix seems to make a properly tuned 50:1 (on pump gas) saw run a fuzz leaner -most likely because it’s a more pure fuel without all the benzene toluene and aromatics added to pump gas. I have manual carb saws and mtronic / autotune saws - I prefer the latter 😀
 

Outback

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32 vs 50 to 1, is a 1 percent difference in fuel energy. 50 vs 100 to 1, is a 1 percent difference in fuel energy. e10 is 3 percent less fuel energy than non ethanol. The difference in your oil mix is more than 3 times less relevant than whether you use ethanol fuel or not as regards the tune.

@7000ft your at 75% sea level air density so a variation of 280ft of altitude on average will equate to 1 percent of your oxygen on the other side of the curve. Using ethanol vs non ethanol equates to an almost 1000ft variation in altitude as regards the perfect tune.

Tuning by oil mix ratio is perhaps the most dubious thing I've ever heard. If 1 percent makes a noticeable difference you're way to lean or way to rich and shouldn't be tuning anything. If your gonna worry about your oil ratio affecting tune start considering your fuel, your altitude and if you're really nuts the temperature and humidity.
 

59billy

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32 vs 50 to 1, is a 1 percent difference in fuel energy. 50 vs 100 to 1, is a 1 percent difference in fuel energy. e10 is 3 percent less fuel energy than non ethanol. The difference in your oil mix is more than 3 times less relevant than whether you use ethanol fuel or not as regards the tune.

@7000ft your at 75% sea level air density so a variation of 280ft of altitude on average will equate to 1 percent of your oxygen on the other side of the curve. Using ethanol vs non ethanol equates to an almost 1000ft variation in altitude as regards the perfect tune.

Tuning by oil mix ratio is perhaps the most dubious thing I've ever heard. If 1 percent makes a noticeable difference you're way to lean or way to rich and shouldn't be tuning anything. If your gonna worry about your oil ratio affecting tune start considering your fuel, your altitude and if you're really nuts the temperature and humidity.
I think that at the end of the day, tuning needs to be about what the saw is doing in the moment. Whether its affected by altitude, oil mix, ambient temperature, ethanol or whatever is interesting as a scientific wank, but that's about it. Keep that screwdriver in your pocket and listen to the saw. Feel the saw. Be the saw.

Okay, ignore the last two sentences. ;)
 
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