YZ250 Muffler Chop Question

FGR01
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FGR01 7/19/2021 1:30pm
7/19/2021 1:30pm
100LL does not contain oxygen additives. It is a great 2-stroke fuel. I would mix 100LL 50/50 with 90 E-free all day long. That will get you right at 95 which is what the Yamaha manual calls for, I believe. Running this mix will not alter your jetting drastically.
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Rickyisms
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Rickyisms 7/19/2021 2:03pm
7/19/2021 2:03pm
FGR01 wrote:
100LL does not contain oxygen additives. It is a great 2-stroke fuel. I would mix 100LL 50/50 with 90 E-free all day long. That will get...
100LL does not contain oxygen additives. It is a great 2-stroke fuel. I would mix 100LL 50/50 with 90 E-free all day long. That will get you right at 95 which is what the Yamaha manual calls for, I believe. Running this mix will not alter your jetting drastically.
Good to know 100LL does not have Oxy content, must've been thinking of something else.
Owen H
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Owen H 7/19/2021 2:19pm
7/19/2021 2:19pm
FGR01 wrote:
100LL does not contain oxygen additives. It is a great 2-stroke fuel. I would mix 100LL 50/50 with 90 E-free all day long. That will get...
100LL does not contain oxygen additives. It is a great 2-stroke fuel. I would mix 100LL 50/50 with 90 E-free all day long. That will get you right at 95 which is what the Yamaha manual calls for, I believe. Running this mix will not alter your jetting drastically.
Man I hear so much dissension on this topic. You’ve been spot on so far so I believe you. I’m currently stock except for the 180 main and everything seems to be running great. I may mix up a separate jug and just give it a test. I want to avoid large changes in jetting as it’s sometbing I’m really not too comfortable with. Im just not that experienced yet. Do you think I can mix 50/50 100LL/90 unleaded and keep my jetting?
FGR01
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FGR01 7/19/2021 3:56pm
7/19/2021 3:56pm
FGR01 wrote:
100LL does not contain oxygen additives. It is a great 2-stroke fuel. I would mix 100LL 50/50 with 90 E-free all day long. That will get...
100LL does not contain oxygen additives. It is a great 2-stroke fuel. I would mix 100LL 50/50 with 90 E-free all day long. That will get you right at 95 which is what the Yamaha manual calls for, I believe. Running this mix will not alter your jetting drastically.
Owen H wrote:
Man I hear so much dissension on this topic. You’ve been spot on so far so I believe you. I’m currently stock except for the 180...
Man I hear so much dissension on this topic. You’ve been spot on so far so I believe you. I’m currently stock except for the 180 main and everything seems to be running great. I may mix up a separate jug and just give it a test. I want to avoid large changes in jetting as it’s sometbing I’m really not too comfortable with. Im just not that experienced yet. Do you think I can mix 50/50 100LL/90 unleaded and keep my jetting?
Mix a small batch, 1 gallon, and try it. Make sure you drain the old fuel completely so that you are getting a true indication of any difference. The jetting difference between 93 pump and the 100LL/90E-free mix will be minimal, if any. Maybe 1 or 2 steps on the pilot, main, or clip. Nothing drastic.
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Owen H
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Owen H 7/20/2021 5:13am
7/20/2021 5:13am
FGR01 wrote:
Mix a small batch, 1 gallon, and try it. Make sure you drain the old fuel completely so that you are getting a true indication of...
Mix a small batch, 1 gallon, and try it. Make sure you drain the old fuel completely so that you are getting a true indication of any difference. The jetting difference between 93 pump and the 100LL/90E-free mix will be minimal, if any. Maybe 1 or 2 steps on the pilot, main, or clip. Nothing drastic.
I'm mostly afraid of bad jetting damaging me or the bike. The actual changing isnt a stress inducer lol. Obviously I dont want to damage the bike. However, I had my old 250SX bog on a big jump face once and it has made me afraid of mistuned 2 strokes ever since hahaha.

What should be more obvious- lean or rich condition?
Do you see there being anything to worry about like my past experience? The tracks here are like asphalt so I'm trying to save all of my crashes for when I go back to FL to ride in my native sand Tongue
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Owen H
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Owen H 7/23/2021 5:21am
7/23/2021 5:21am
FGR01 wrote:
100LL does not contain oxygen additives. It is a great 2-stroke fuel. I would mix 100LL 50/50 with 90 E-free all day long. That will get...
100LL does not contain oxygen additives. It is a great 2-stroke fuel. I would mix 100LL 50/50 with 90 E-free all day long. That will get you right at 95 which is what the Yamaha manual calls for, I believe. Running this mix will not alter your jetting drastically.
Would I be able to remedy the pump gas thing by purchasing a quality bolt on head with the interchangeable domes? Just a thought. Thanks again for all your help (:

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