I'm goin have to run race gas to break in my motor I only plan to get 2 gallons of gas So my question is wat the breakdown on how much oil I should And also wat kind of oil
Race Gas
- Thread starter BlasterCrazy
- Start date
Why are you going to run race gas for a break-in? The break in should probably be done with the same fuel you intend to use for the duration of riding.
Race gas (or the easier to procure AvGas) is usually an exotic blend of distillates with additives not usually found in pump fuel. Sometimes including lead additives which can foul rings.
As for oil, I use Klotz super techniplate because it's a castor blend and smells pretty sweet... plus it's sterile and I like the taste! (sorry cheap movie quote). I know a guy who built a blasty engine up from scrap and only runs 87 octane with the cheapest 2 stroke oil money can buy mixed 32:1 and it's still chugging right along.
As for ratio, start off thick and move thinner as you get out of the "idling period" Mix the first gallon like 25:1 and then after that move up towards 32:1. Worked great for me!
Race gas (or the easier to procure AvGas) is usually an exotic blend of distillates with additives not usually found in pump fuel. Sometimes including lead additives which can foul rings.
As for oil, I use Klotz super techniplate because it's a castor blend and smells pretty sweet... plus it's sterile and I like the taste! (sorry cheap movie quote). I know a guy who built a blasty engine up from scrap and only runs 87 octane with the cheapest 2 stroke oil money can buy mixed 32:1 and it's still chugging right along.
As for ratio, start off thick and move thinner as you get out of the "idling period" Mix the first gallon like 25:1 and then after that move up towards 32:1. Worked great for me!
with the mods listed in my sig im only pushing around 160psi and i dont need race gas. so unless you are more modded you are just wasting your money.
If your motor isn't designed for race gas, you're just wasting money. It will also hurt performance.
Yep not worth it for play riding in my opinion. A motor makes maximum power with the lowest possible octane that doesn't cause predetonation.
I'm not sure I agree with this quote though. Changing the oil/fuel mix also changes your air/fuel ratio. 25:1 would cause you to run richer, I think, but still my gut says break it in like you are going to use it.
Actually 25:1 is leaner than 32:1. Regardless of ratio, the same amount of liquid will flow through the carb. Additional oil displaces fuel resulting in a leaner condition. Different mix ratios change your A/F ratios because of the different amounts of fuel... resulting in different jetting needs. Make sense? :-/ haha
With that said, I agree, break in with the same ratio you intend to run afterwards.
Yeah 25:1 is leaner. More oil takes up space instead of fuel, so same amount of air atomizes with less fuel. Leaner.
I dont remember what the PSI was on my CT 240 after break in but I dont think it was much higher then 160 psi, I might be wrong.
I hope I did not F it up
CT recommended a 50/50 mix of race gas and pump gas and 32:1 break in then 40:1 after the 1st tank of gas
Now I want to do a compression check.X( Anyone know what my psi should be?
I just got my new tank on to and now its time to take it off.X(
I dont remember what the PSI was on my CT 240 after break in but I dont think it was much higher then 160 psi, I might be wrong.
I hope I did not F it up
CT recommended a 50/50 mix of race gas and pump gas and 32:1 break in then 40:1 after the 1st tank of gas
Now I want to do a compression check.X( Anyone know what my psi should be?
I just got my new tank on to and now its time to take it off.X(
i belive mr 305 said his psi was around 180 or 190 and hes got a ct kit.
just to throw my 2 pennies in here my manual for my yz 250 says break the engine in at 15:1 and then move up
Thanks
The last time I did a compression test was about 1 year ago. It sat all winter and I decided to do a test before I got it out for the riding season. The compression test appeard low, and my buddy said I was a dumb ass, the motor sat all winter, its dry give it some lub, and do it again. WE did and I think It might of been 175 psi, but I dont realiy remember.
Thanks again nooberI:I
Well according to the break in proceudres for two strokes you shouldn't be doing anything more than idling for the first 20-30 minute the engine is running AND you're supposed to richen up the air screw anyway so you won't be running lean. So how much gas are you actually displacing with oil at idle with the air screw turned up for more fuel?
Anyway, Husqvarna did a test series (imperical data) which ran a series of test engines at different oil ratios right down to like 10:1 on a test bench hooked to a dynamometer. Using petroleum based lubricants they were able to keep an engine together at 50:1 and increments down to 10:1. Guess where engine put out the most power? At around 20:1the engine put out the most amount of power but the spark plug didn't last long.
Anyone care to guess why the engine put out the most power at 20:1? Most think of oil as ONLY lubrication in a 2 stroke but it also burns too. Which brings us to our next lesson...
Fuel volitility (reed vapor pressure) vs. energy storage (BTU's)
Generally speaking, fuel that burns quickly doens't contain as much energy as fuel that burns slowly. kerosene vs. gasoline is a good example. Or an even better example but not as easy to understand is straw/hay vs. gasoline. Straw takes a certain set of criteria to ignite but contains a LOT of energy per pound where as any vaporized gasoline will ignite but only burn for a few seconds and then go out.
Gasoline is a good compromise however because straw is hard to get into a cylinder, compress, and back out of a cylinder quickly...
Now, for what thinking that oil is ONLY a lubricant gets you... Petroleum based 2 stroke oil will burn if heated enough. When the conditions get right and it does burn, it holds more energy in it than the comparable (by volume) amount of gasoline. When the gasoline is used to get the fire going, the oil burns and releases its energy which is actually more by volume.
Now, a few caveats about lean vs. rich mixture and energy density vs. spark plug life:
It's fairly common knowledge that a lean condition will put out more "power" than a rich condition. But this is only true in a limited amount of cases. A lean mixture is more vaporized with more oxygen around each molecule of gasoline so when the spark plug goes off the reaciton is quicker than when there is more fuel present. At high RPM's where volumetric efficiency suffers this "quick" burn of a lean engine means that it continues to put out the SAME amount of power as the RPM's grow instead of reduced power. But ESPECIALLY on an air cooled engine, a lean mixture also burns hotter and will burn up an engine.
While oil contains more energy by volume than gasoline, it also cokes a LOT more than gasoline. Everything from gasoline up towards the lighter distillates burns with almost no smoke as long as the AFR is kept in a reasonable level. Oil is NOT above gasoline in volitility and burns but not completely results in ash or coke. That ash just clogs up all kinds of stuff including ring gaps and spark plugs resulting in less performance over the long run. A higher ratio (less oil) reduces ash extending out the life span a bit. 32:1 is a good compromise that results in less ash and enough lubrication to keep the engine alive.
Anyway, Husqvarna did a test series (imperical data) which ran a series of test engines at different oil ratios right down to like 10:1 on a test bench hooked to a dynamometer. Using petroleum based lubricants they were able to keep an engine together at 50:1 and increments down to 10:1. Guess where engine put out the most power? At around 20:1the engine put out the most amount of power but the spark plug didn't last long.
Anyone care to guess why the engine put out the most power at 20:1? Most think of oil as ONLY lubrication in a 2 stroke but it also burns too. Which brings us to our next lesson...
Fuel volitility (reed vapor pressure) vs. energy storage (BTU's)
Generally speaking, fuel that burns quickly doens't contain as much energy as fuel that burns slowly. kerosene vs. gasoline is a good example. Or an even better example but not as easy to understand is straw/hay vs. gasoline. Straw takes a certain set of criteria to ignite but contains a LOT of energy per pound where as any vaporized gasoline will ignite but only burn for a few seconds and then go out.
Gasoline is a good compromise however because straw is hard to get into a cylinder, compress, and back out of a cylinder quickly...
Now, for what thinking that oil is ONLY a lubricant gets you... Petroleum based 2 stroke oil will burn if heated enough. When the conditions get right and it does burn, it holds more energy in it than the comparable (by volume) amount of gasoline. When the gasoline is used to get the fire going, the oil burns and releases its energy which is actually more by volume.
Now, a few caveats about lean vs. rich mixture and energy density vs. spark plug life:
It's fairly common knowledge that a lean condition will put out more "power" than a rich condition. But this is only true in a limited amount of cases. A lean mixture is more vaporized with more oxygen around each molecule of gasoline so when the spark plug goes off the reaciton is quicker than when there is more fuel present. At high RPM's where volumetric efficiency suffers this "quick" burn of a lean engine means that it continues to put out the SAME amount of power as the RPM's grow instead of reduced power. But ESPECIALLY on an air cooled engine, a lean mixture also burns hotter and will burn up an engine.
While oil contains more energy by volume than gasoline, it also cokes a LOT more than gasoline. Everything from gasoline up towards the lighter distillates burns with almost no smoke as long as the AFR is kept in a reasonable level. Oil is NOT above gasoline in volitility and burns but not completely results in ash or coke. That ash just clogs up all kinds of stuff including ring gaps and spark plugs resulting in less performance over the long run. A higher ratio (less oil) reduces ash extending out the life span a bit. 32:1 is a good compromise that results in less ash and enough lubrication to keep the engine alive.
Was the compression raised significantly? Porting won't need to run high octane fuel specifically although to take full advantage of possible timing modifications you may need higher octance fuel. 4 degrees timing increase should still be on the safe side as long as you run only 93 octane.
If you are going for high octane fuel, you NEED to find something other than AvGas.
Look for VP racing VP100 or something similar NOT 100LL from the local airport. They are not the same and should not be used interchangably. Otherwise, you may need to responsibly question your engine porter. 93 octane fuel is running about $3 a gallon 100 octane is going to be $8 plus and C16 or something even higher octance is going to run about $14 a gallon and you can't ship some of it because of DOT regulations which means you pay whatever someone local wants for it. If you want to pay big money for fuel you don't actually NEED go right ahead.
If you are going for high octane fuel, you NEED to find something other than AvGas.
Look for VP racing VP100 or something similar NOT 100LL from the local airport. They are not the same and should not be used interchangably. Otherwise, you may need to responsibly question your engine porter. 93 octane fuel is running about $3 a gallon 100 octane is going to be $8 plus and C16 or something even higher octance is going to run about $14 a gallon and you can't ship some of it because of DOT regulations which means you pay whatever someone local wants for it. If you want to pay big money for fuel you don't actually NEED go right ahead.
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