AV Gas for 2 strokes..

HazemG
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9/16/2014 9:37am Edited Date/Time 9/17/2014 1:28pm
Heard the YZ's don't like pump gas.. would AV Gas mixed 32:1 or 40:1 work? What is your preferred premix brand? Going to pick some up today.
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Psc19933
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9/16/2014 9:45am
I always liked half premium pump and half av gas. Even though it is called 100 low lead it has A LOT of lead in it, more than any street gas ever had in it.
HazemG
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9/16/2014 9:52am
Psc19933 wrote:
I always liked half premium pump and half av gas. Even though it is called 100 low lead it has A LOT of lead in it...
I always liked half premium pump and half av gas. Even though it is called 100 low lead it has A LOT of lead in it, more than any street gas ever had in it.
Sounds like a plan to me. What premix should I use with the YZ and at what ratio do you recommend? I just rebuilt the bike so I want to take care of it.
DownSouth
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9/16/2014 9:57am
I have always used Yamalube R at 32:1 in my YZ 250's. 40:1 will probably make no difference but I always went 32:1 to have a bit more lube in the mix.

You will get dozens of opinions on oil brands and ratios, as everyone has their own preference.
CamP
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9/16/2014 10:09am Edited Date/Time 9/16/2014 10:10am
100LL is good 2-stroke fuel. It's only $5/gal around here, so I just run it straight.

The oil ratio depends on the type of oil, your skill level and what type of dirt you ride.

The Shop

Psc19933
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9/16/2014 10:14am
Any good name brand oil for water cooled two strokes at 38 to 1 always worked for me.
hillbilly
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9/16/2014 10:18am
When you add more oil you are leaning the engine out on fuel air ratio..
MP818
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9/16/2014 10:25am Edited Date/Time 9/16/2014 10:26am
I've been running the 100LL that CamP mentioned in my '14 YZ250. I'm a half ass has-been A rider running 36:1 Maxima Castor 927 with straight av gas. Stock carb with a 175 main, 50 pilot and clip 2nd from the top on the needle. Plug is always a crispy brown.
IWreckALot
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9/16/2014 10:29am
CamP wrote:
100LL is good 2-stroke fuel. It's only $5/gal around here, so I just run it straight. The oil ratio depends on the type of oil, your...
100LL is good 2-stroke fuel. It's only $5/gal around here, so I just run it straight.

The oil ratio depends on the type of oil, your skill level and what type of dirt you ride.
I've been running 50/50 av gas/premium. You get your av gas from hicks airfield? Where else can you get it around the DFW?

I run belray 2 stroke oil at 32:1 in my 2013 YZ250. I have only fouled one plug in 8 months. And it runs pretty strong. I've let 2 or 3 other people ride my bike and they all think it runs pretty strong. It's my first 2 stroke so I don't have anything to gauge it against.
hillbilly
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9/16/2014 10:38am
Castor oil breaks down in about 2 weeks, I never went past a week and just poured it in weedeater,tractor or one of my old fords.
MP818
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9/16/2014 10:44am Edited Date/Time 9/16/2014 10:45am
hillbilly wrote:
Castor oil breaks down in about 2 weeks, I never went past a week and just poured it in weedeater,tractor or one of my old fords.
Castor is amazing! All of Maxima's products are great. I'm in the habit of draining my tank after I ride and always shaking my can before filling up my bike. It does break down, I'll give you that. The simple solution to that (I've always heard) is shaking your can. Plus I usually get new gas every time I ride. 3-5 gallons a day
MP818
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9/16/2014 10:46am Edited Date/Time 9/16/2014 2:54pm
CamP wrote:
100LL is good 2-stroke fuel. It's only $5/gal around here, so I just run it straight. The oil ratio depends on the type of oil, your...
100LL is good 2-stroke fuel. It's only $5/gal around here, so I just run it straight.

The oil ratio depends on the type of oil, your skill level and what type of dirt you ride.
IWreckALot wrote:
I've been running 50/50 av gas/premium. You get your av gas from hicks airfield? Where else can you get it around the DFW? I run belray...
I've been running 50/50 av gas/premium. You get your av gas from hicks airfield? Where else can you get it around the DFW?

I run belray 2 stroke oil at 32:1 in my 2013 YZ250. I have only fouled one plug in 8 months. And it runs pretty strong. I've let 2 or 3 other people ride my bike and they all think it runs pretty strong. It's my first 2 stroke so I don't have anything to gauge it against.
Delete
hillbilly
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9/16/2014 10:56am
hillbilly wrote:
Castor oil breaks down in about 2 weeks, I never went past a week and just poured it in weedeater,tractor or one of my old fords.
MP818 wrote:
Castor is amazing! All of Maxima's products are great. I'm in the habit of draining my tank after I ride and always shaking my can before...
Castor is amazing! All of Maxima's products are great. I'm in the habit of draining my tank after I ride and always shaking my can before filling up my bike. It does break down, I'll give you that. The simple solution to that (I've always heard) is shaking your can. Plus I usually get new gas every time I ride. 3-5 gallons a day
Yeah,I thought I read the oil molecule breaks down or such, I always liked pouring it in all my other engines so the smell was always around.
FGR01
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Fantasy
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9/16/2014 10:58am
I run Maxima Super-M at 32:1 in both my YZ125 and 250. Both bikes run super strong and crisp and have never had a problem in over 5 years. Top ends come out nice and clean with easy power valve cleaning when I rebuild them. In my mind, there is no reason to run Castor oil other than the cool smell or unless you like repacking silencers clogged with carbon.
Cygnus
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9/16/2014 11:00am
Psc19933 wrote:
I always liked half premium pump and half av gas. Even though it is called 100 low lead it has A LOT of lead in it...
I always liked half premium pump and half av gas. Even though it is called 100 low lead it has A LOT of lead in it, more than any street gas ever had in it.
Wrong, leaded fuel back In the seventies had 4 grams per gallon. 100LL only has .59 of a gram at most . Watch what you guys are getting and ask for a spec sheet on the fuel. All lead will be gone before 2023 as per the EPA. Maybe sooner with all the new aviation fuels coming out.
MP818
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9/16/2014 11:09am
hillbilly wrote:
Castor oil breaks down in about 2 weeks, I never went past a week and just poured it in weedeater,tractor or one of my old fords.
MP818 wrote:
Castor is amazing! All of Maxima's products are great. I'm in the habit of draining my tank after I ride and always shaking my can before...
Castor is amazing! All of Maxima's products are great. I'm in the habit of draining my tank after I ride and always shaking my can before filling up my bike. It does break down, I'll give you that. The simple solution to that (I've always heard) is shaking your can. Plus I usually get new gas every time I ride. 3-5 gallons a day
hillbilly wrote:
Yeah,I thought I read the oil molecule breaks down or such, I always liked pouring it in all my other engines so the smell was always...
Yeah,I thought I read the oil molecule breaks down or such, I always liked pouring it in all my other engines so the smell was always around.
I always heard it settles, not really breaks down. I do know it seperates if you mix it with a different kind of oil which I've seen turn pretty bad. I may check out that Maxima Super-M FGR01. Does it run more expensive from Maxima?
newmann
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9/16/2014 11:10am
Pick your oil, read the label and jet it for HazemG. I have bikes that run 32:1, 50:1 and 60:1, all different bikes, all different oils and all different fuels.
RACERX69
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9/16/2014 11:15am Edited Date/Time 9/16/2014 11:17am
I'd be careful running straight AV-Gas. Aircraft engines only run about 2500 RPM and AV-Gas is formulated as such. Most mechanics I know advise against using it as it supposedly creates higher combustion temps.
YZ125H1
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9/16/2014 11:19am
newmann wrote:
Pick your oil, read the label and jet it for HazemG. I have bikes that run 32:1, 50:1 and 60:1, all different bikes, all different oils...
Pick your oil, read the label and jet it for HazemG. I have bikes that run 32:1, 50:1 and 60:1, all different bikes, all different oils and all different fuels.
This ^ There is no perfect ratio its really based on the oil you are using, rider application/skill level, and jetting.
Cygnus
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9/16/2014 11:22am
Just find some good race gas and jet for it. Av gas I ok but not great.

Here's a good read.

Racing Gasoline Verses Aviation Gasoline

written by, and thanks to Tim Wusz 76 Products Company

I am going to attempt to address the controversy of aviation gasoline verses racing gasoline for use in race cars. Some racers use aviation gasoline which is fine for some applications but does have shortcomings. There are several grades of aviation gasoline (avgas) that we must identify before going any farther.

1. Avgas 80/87: this product is used in low compression ratio aircraft engines, contains little or no lead, is red in color, and should not be used in any automotive engine due to a low motor octane number of about 80.

2. Avgas 100/130: this product that can be used in some automotive engines. It has both research and motor octane numbers slightly over 100. Avgas 100/130 is green in color, contains four grams of lead per gallon, and is becoming harder to find.

3. Avgas 100 LL: the LL stands for "low-lead" which means two grams per gallon, low compared to the avgas 100/130 that it was designed to replace. It has research and motor octane numbers very similar to the 100/130 product previously discussed. The color is blue. This product sometimes has a high level of aromatics which can contribute to lazy throttle response and dissatisfaction of the consumer.

4. Avgas 115/145: this product was developed for high performance piston aircraft engines used in world war II and in the Korean war. It is very hard to find anymore due to lack of demand although it is of very high octane quality. The color is purple.


The remainder of this discussion will assume that our basis for comparison with racing gasoline is avgas 100/130 and/or 100 LL since they are both available and have acceptable octane quality for limited applications. When the word "avgas" is used, it will refer to avgas 100/130 or 100 LL.

Avgas is less dense than most racing gasolines. Instead of weighing about 6.1 to 6.3 pounds per gallon like racing gasoline, it weighs 5.8 to 5.9 pounds per gallon. The racer must compensate for this by changing to richer (larger) jets in the carburetor when changing from racing gasoline to avgas.

The other major difference is octane quality. Avgas is short on octane compared to most racing gasolines. Many racing engines with "quick" spark advance curves or with no centrifugal advance have more spark advance at low rpm than avgas and some racing gasolines can handle. The result is detonation, especially during caution periods in circle track racing because all of the spark advance is "in", rpm is low, and part throttle air fuel ratios are too lean for the operating conditions. If the driver does not "work" the throttle back and forth, pistons can be "burned" which melts away part of the aluminum piston material. Inadequate octane quality is one of the quickest ways to destroy an engine. Pistons can be severely damaged during one acceleration where detonation is present and the racer may not know what is happening until it is too late.

For maximum performance and power from a racing engine, racing gasoline will normally provide better performance than avgas. Avgas can be a good gasoline for some applications, but since most racers do not know the octane requirement of their engines, they would be better off with a "real" racing gasoline that will give them the overall resistance to detonation that they need to protect their investment. If someone has spent from $15,000 to $50,000 or more on their racing engine, it is foolish to cut corners on gasoline be sure you have a gasoline with adequate octane quality.
MP818
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9/16/2014 11:29am
Good read Cygnus. Has anyone ever combined say 2 gallons of VP110 and 2 gallons of 100LL? Or is that a bug no no?
HazemG
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9/16/2014 11:47am
Cygnus wrote:
Just find some good race gas and jet for it. Av gas I ok but not great. Here's a good read. Racing Gasoline Verses Aviation Gasoline...
Just find some good race gas and jet for it. Av gas I ok but not great.

Here's a good read.

Racing Gasoline Verses Aviation Gasoline

written by, and thanks to Tim Wusz 76 Products Company

I am going to attempt to address the controversy of aviation gasoline verses racing gasoline for use in race cars. Some racers use aviation gasoline which is fine for some applications but does have shortcomings. There are several grades of aviation gasoline (avgas) that we must identify before going any farther.

1. Avgas 80/87: this product is used in low compression ratio aircraft engines, contains little or no lead, is red in color, and should not be used in any automotive engine due to a low motor octane number of about 80.

2. Avgas 100/130: this product that can be used in some automotive engines. It has both research and motor octane numbers slightly over 100. Avgas 100/130 is green in color, contains four grams of lead per gallon, and is becoming harder to find.

3. Avgas 100 LL: the LL stands for "low-lead" which means two grams per gallon, low compared to the avgas 100/130 that it was designed to replace. It has research and motor octane numbers very similar to the 100/130 product previously discussed. The color is blue. This product sometimes has a high level of aromatics which can contribute to lazy throttle response and dissatisfaction of the consumer.

4. Avgas 115/145: this product was developed for high performance piston aircraft engines used in world war II and in the Korean war. It is very hard to find anymore due to lack of demand although it is of very high octane quality. The color is purple.


The remainder of this discussion will assume that our basis for comparison with racing gasoline is avgas 100/130 and/or 100 LL since they are both available and have acceptable octane quality for limited applications. When the word "avgas" is used, it will refer to avgas 100/130 or 100 LL.

Avgas is less dense than most racing gasolines. Instead of weighing about 6.1 to 6.3 pounds per gallon like racing gasoline, it weighs 5.8 to 5.9 pounds per gallon. The racer must compensate for this by changing to richer (larger) jets in the carburetor when changing from racing gasoline to avgas.

The other major difference is octane quality. Avgas is short on octane compared to most racing gasolines. Many racing engines with "quick" spark advance curves or with no centrifugal advance have more spark advance at low rpm than avgas and some racing gasolines can handle. The result is detonation, especially during caution periods in circle track racing because all of the spark advance is "in", rpm is low, and part throttle air fuel ratios are too lean for the operating conditions. If the driver does not "work" the throttle back and forth, pistons can be "burned" which melts away part of the aluminum piston material. Inadequate octane quality is one of the quickest ways to destroy an engine. Pistons can be severely damaged during one acceleration where detonation is present and the racer may not know what is happening until it is too late.

For maximum performance and power from a racing engine, racing gasoline will normally provide better performance than avgas. Avgas can be a good gasoline for some applications, but since most racers do not know the octane requirement of their engines, they would be better off with a "real" racing gasoline that will give them the overall resistance to detonation that they need to protect their investment. If someone has spent from $15,000 to $50,000 or more on their racing engine, it is foolish to cut corners on gasoline be sure you have a gasoline with adequate octane quality.
If I don't have an easy way to get VP, but can get AV readily, is it going to be better to cut AV gas with premium pump, or just straight premium pump???
CamP
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9/16/2014 12:16pm
RACERX69 wrote:
I'd be careful running straight AV-Gas. Aircraft engines only run about 2500 RPM and AV-Gas is formulated as such. Most mechanics I know advise against using...
I'd be careful running straight AV-Gas. Aircraft engines only run about 2500 RPM and AV-Gas is formulated as such. Most mechanics I know advise against using it as it supposedly creates higher combustion temps.
You heard wrong. Straight 100LL works great. Been using it for over 30 years in my 2-strokes. Cylinder head temps for my bikes generally run 140-145F when I pull off the track in the summer.
9/16/2014 12:16pm
I ran avgas for months in my '13 YZ250 with no issues - and I ran it straight with Redline oil. Then I found a Base Race Fuel distributor and started running straight 114 octane race fuel with Redline oil. I never had problems with either of them.

Base Race Fuel is $10 a gallon versus $18 for VP. That extra octane in Base makes the mid-range kick like a mule.
HazemG
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9/16/2014 12:17pm
Cygnus wrote:
I'd go with this and a decent octane booster truthfully if you hang get Sunoco or other race gas. Lucas oil has a good one.

http://pure-gas.org/index.jsp?stateprov=KS
thanks for the link. I found a place with 91 octane pure gas (no ethanol) in my city. Is that what you were referring to? And what kind of octane booster.. one I can pick up at advance/oreilys?
CamP
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9/16/2014 12:19pm
MP818 wrote:
I always heard it settles, not really breaks down. I do know it seperates if you mix it with a different kind of oil which I've...
I always heard it settles, not really breaks down. I do know it seperates if you mix it with a different kind of oil which I've seen turn pretty bad. I may check out that Maxima Super-M FGR01. Does it run more expensive from Maxima?
Max, just be careful running 927 in the winter. It separates from the low specific gravity fuels when it's cold outside.
CamP
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9/16/2014 12:20pm
HazemG wrote:
thanks for the link. I found a place with 91 octane pure gas (no ethanol) in my city. Is that what you were referring to? And...
thanks for the link. I found a place with 91 octane pure gas (no ethanol) in my city. Is that what you were referring to? And what kind of octane booster.. one I can pick up at advance/oreilys?
You would be safer with 100LL.
HazemG
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9/16/2014 12:27pm
CamP wrote:
You would be safer with 100LL.
Thanks Cam, say no more
FGR01
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Fantasy
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9/16/2014 12:30pm
MP818 wrote:
I always heard it settles, not really breaks down. I do know it seperates if you mix it with a different kind of oil which I've...
I always heard it settles, not really breaks down. I do know it seperates if you mix it with a different kind of oil which I've seen turn pretty bad. I may check out that Maxima Super-M FGR01. Does it run more expensive from Maxima?
I believe Super-M is actually cheaper than Castor-927. Super-M is a semi-synthetic oil. Formula-K2 is Maxima's top of the line full-synthetic. I tried K2 before and found that the bike was not quite as crisp and had a hint of drool out the muffler. I believe this may be due to K2 having a higher flash point than Super-M and therefore not burning quite as easily/cleanly. So I went back to Super-M and have been good ever since.

Another bad thing about Castor oil. When it breaks down it releases stearic acid. Stearic acid is corrosive to brass. Not a good thing for your carburetor. If you run castor oil it is not advisable to let it sit in your carb during prolonged storage.
CamP
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9/16/2014 12:49pm Edited Date/Time 9/16/2014 12:57pm
MP818 is a local Texas pro. He's fast enough that I would recommend that he stick with 927 in the summer and run K2 in the winter when it's under 50F, or run K2 year round.

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