just about every one recomends putting some two stroke oil in the fuel tank on a new top end or fresh motor despite the oiler. the only problem with this is now you have less gas that is going to burn in the cylinder and the same amount of air coming into the motor thus causing a lean affect. any thoughts?
NO OIL IN GAS ON FRESH MOTOR???
- Thread starter bm919mx
- Start date
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clutch man
Well-known member
a double edge sword
You have some facts here but!! and a big but! By putting in oil in the first tank of gas just give you the insurance that all the air bubbles our gone by the time the oil in the tank runs out!
The fact that you have so little oil (say 40-1) it will take up so little space that it will not even effect the lean down or if it does not much at all.
Good food for thought great post.
like to hear others way in here.
You have some facts here but!! and a big but! By putting in oil in the first tank of gas just give you the insurance that all the air bubbles our gone by the time the oil in the tank runs out!
The fact that you have so little oil (say 40-1) it will take up so little space that it will not even effect the lean down or if it does not much at all.
Good food for thought great post.
like to hear others way in here.
What kind of oil are you using?
The oil mixes with the fuel and you have the exact same amount of fuel. Oil burns too so it is not like you are putting something non flammable in there. If anything the effect of putting oil in their would be to raise the octane slightly and make the fuel less prone to pre-ignition.
Polaris does it from the factory, Indy Dan recommends it in every tank for good reason.
The 900's are notorious for overheating the mag side pistons, not just from being lean but from lack of lubrication. I don't think there is much that will piss you off more than melting down the piston in a motor on the first ride after spending a ton of money rebuilding it.
Polaris does it from the factory, Indy Dan recommends it in every tank for good reason.
The 900's are notorious for overheating the mag side pistons, not just from being lean but from lack of lubrication. I don't think there is much that will piss you off more than melting down the piston in a motor on the first ride after spending a ton of money rebuilding it.
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12 oz of oil in every tank of fuel.
=about 120:1 on top of the stock oil injection (40:1) and you will be MUCH better off then not mixing your tank at all
=about 120:1 on top of the stock oil injection (40:1) and you will be MUCH better off then not mixing your tank at all
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bustamove
Active member
funny story, rebuilt my whole engine cases everything, mag side blew up but i was running pre mix. what causes the mag side to overheat? improper coolant filling?
when you mix oil with the gas the second that it mixes your octane rating goes down. when you have more air then gas then you have a lean effect. so at this point we have lowered our octane rating and leaned our new motor out. when you have the 900 apart you will find that the lube paths on both the mag and pto side are the same. everthing that i read the mag side goes from a lean condition not from lack of lube. the amount of oil maybe so little that it has no effect but when ever you mix oil and gas for say your weed eater and you dump just a little extra in that will casue them to lean out. so basically the same with your sled.
Bet that story wasn't very funny at the time. A bunch of things can cause it; cooling not as good on mag side, if your crank seal leaks it runs lean and causes it, if your injectors are not putting out enough fuel, cracks in the intake boots, oxygenated Fuel or fuel with ethanol added.
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Octane does not work that way. Oil is not more explosive than gas. The higher the octane the slower the fuel burns. A lower octane fuel will ignite off just compression. Using your theory of oil lowering your octane the compression ratios would have to be lowered or we would have to all run av gas.
A weed eater running 100:1 or 50:1 fuel oil ratio with 20cc to 26cc displacement is in no way comparable to a snowmobile engine. The amount of fuel the weed eater uses is so minute that any change in the burn characteristics will affect it. The amount of fuel it takes for a weed eater to run for half and hour would barely run a 900 out of the parking lot.
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found this
The most important characteristic of petrol is its Research Octane Number (RON) or octane rating, which is a measure of how resistant petrol is to premature detonation (knocking). It is measured relative to a mixture of isooctane (2,2,4-trimethylpentane) and n-heptane. So an 87-octane petrol has the same knock resistance as a mixture of 87% isooctane and 13% n-heptane.
There is another type of Octane, called "Motor Octane Number" (MON), which is a better measure of how the fuel behaves when under load. Its definition is also based on the mixture of isooctane and n-heptane that has the same performance. Depending on the composition of the fuel, the MON of a modern petrol will be about 10 points lower than the RON. Normally fuel specifications require both a minimum RON and a minimum MON.
In most countries (including all of Europe and Australia) the 'headline' octane that would be shown on the pump is the RON: but in the United States and some other countries the headline number is in fact the average of the RON and the MON, sometimes called the "Road Octane Number" or RON. Because of the 10 point difference noted above this means that the octane in the United States will be about 5 points lower than the same fuel elsewhere: 87 octane fuel in the United States would be 92 in Europe.
It is possible for a fuel to have a RON greater than 100. This reflects the fact that isooctane is not the most knock-resistant substance available. Racing fuels, Avgas and LPG typically have octane ratings of 110 or significantly higher.
It might seem odd that fuels with higher octane ratings burn less easily, yet are popularly thought of as more powerful. Using a fuel with a higher octane allows an engine to be run at a higher compression ratio without having problems with knock. Compression is directly related to power, so engines that require higher octane usually deliver more power. Some high-performance engines are designed to operate with a compression ratio associated with high octane numbers, and thus demand high-octane petrol. It should be noted that the power output of an engine also depends on the energy content of its fuel, which bears no simple relationship to the octane rating. Some people believe that adding a higher octane fuel to their engine will increase its performance or lessen its fuel consumption. This is false - engines perform best when using fuel with the octane rating they were designed for.
The most important characteristic of petrol is its Research Octane Number (RON) or octane rating, which is a measure of how resistant petrol is to premature detonation (knocking). It is measured relative to a mixture of isooctane (2,2,4-trimethylpentane) and n-heptane. So an 87-octane petrol has the same knock resistance as a mixture of 87% isooctane and 13% n-heptane.
There is another type of Octane, called "Motor Octane Number" (MON), which is a better measure of how the fuel behaves when under load. Its definition is also based on the mixture of isooctane and n-heptane that has the same performance. Depending on the composition of the fuel, the MON of a modern petrol will be about 10 points lower than the RON. Normally fuel specifications require both a minimum RON and a minimum MON.
In most countries (including all of Europe and Australia) the 'headline' octane that would be shown on the pump is the RON: but in the United States and some other countries the headline number is in fact the average of the RON and the MON, sometimes called the "Road Octane Number" or RON. Because of the 10 point difference noted above this means that the octane in the United States will be about 5 points lower than the same fuel elsewhere: 87 octane fuel in the United States would be 92 in Europe.
It is possible for a fuel to have a RON greater than 100. This reflects the fact that isooctane is not the most knock-resistant substance available. Racing fuels, Avgas and LPG typically have octane ratings of 110 or significantly higher.
It might seem odd that fuels with higher octane ratings burn less easily, yet are popularly thought of as more powerful. Using a fuel with a higher octane allows an engine to be run at a higher compression ratio without having problems with knock. Compression is directly related to power, so engines that require higher octane usually deliver more power. Some high-performance engines are designed to operate with a compression ratio associated with high octane numbers, and thus demand high-octane petrol. It should be noted that the power output of an engine also depends on the energy content of its fuel, which bears no simple relationship to the octane rating. Some people believe that adding a higher octane fuel to their engine will increase its performance or lessen its fuel consumption. This is false - engines perform best when using fuel with the octane rating they were designed for.
that was just a thought but either way do we agree that it leans out your motor. maybe not enough to make a difference but it still leans it out
Possibly but again 20cc vs 866cc. You could add or remove the entire amount of fuel that the weed eater burns to the fuel being supplied to the 900 engine and probably would not be able to tell any difference.
Because of the small size of the weed eater engine less oil can be run in it with ratios as high as 100:1. If you tried to run 100:1 in your 900 it would seize the engine in a very short time.
right the weed eater was just an example. you just need to be careful how much oil you put in your tank on your sled if any at all
kinda off the subject but when i was racing dirt bikes alot of those guys would run AMS oil at 50:1 when the rest of us were 32:1 is the oil that good or where they just riding a time bomb
Synthetic oil has better lubrication properties. This is a whole other discussion on here because some of the synthetics do not have the rust prevention capabilities of conventional oils so there is a big debate over which is better in a 2 cycle snowmobile engine. Indydan recommends conventional oil.
I switched my truck over to Amsoil and got a 2-3 mpg increase in the city and 5-8 mpg increase on the highway. That is enough to convince me it is doing something.
i think that as long as you are cleaning your power valves you can run what ever oil you want. i prefer syntheics. i acutally run polaris ves gold. do you think that its that important
Yes, keeping the exhaust valve clean is important. There are a couple threads that discuss oil. here is one http://www.snowestonline.com/forum/showthread.php?t=92802
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bustamove
Active member
lol its not, its been a big learning curve the mag side has blown up twice now. cant be any seal leaks replaced them all, replaced crack, cases, both jugs, head, pistons, all bearings, reeds. only thing i didn't do was replace injectors which im doing now.. hopefull its doesn't grenade on me this time.
what if you add octane booster with oil in the first tank to eliminate detonation?
Are you having a detonation problem? If you want to add octane booster to your fuel make sure it is for use in 2 cycle snowmobile engines.
I would have the injectors tested if you can, or at least the one on the side that failed. If it test out perfect then you know that you may have a problem still.
Couple questions.
What type of pistons were you using that failed?
Were you using Oxygenated or non-oxygenated fuel. They sell non-oxygenated fuel in Montana where I ride just for snowmobiles. The Oxygenated/ethanol Fuels make the engines run hotter.
Did you check your oil injection pump and the lines going to that side of the engine?
I would have the injectors tested if you can, or at least the one on the side that failed. If it test out perfect then you know that you may have a problem still.
Couple questions.
What type of pistons were you using that failed?
Were you using Oxygenated or non-oxygenated fuel. They sell non-oxygenated fuel in Montana where I ride just for snowmobiles. The Oxygenated/ethanol Fuels make the engines run hotter.
Did you check your oil injection pump and the lines going to that side of the engine?
