Oil/gas mix - What is correct and does it very?

sofasurferlinux · #1 07-11-2009, 10:11 AM

My manual for chinese Jet Silver 80cc says to start with 16:1 and after breakin use 20:1. They are saying to go from more oil to less oil. The forums say to start with 20:1 or so and progress to 40 or 50:1, unless I and misreading something.

Can someone verify the proper mixes and explain what they do?
Do they very from motor to motor?
Does the octane rating in the gas matter or do we just use whats available?
And a little extra learning...Why does a car engine have massive amounts of oil being thrown all over everything but a 2 cycle only needs an amount that is virtually undetectable? They still work like **** and build up as much heat as ****.

Ghost0 · #2 07-11-2009, 10:33 AM

I think 16:1 is just too much oil and would recommend 20:1 for break in. After 4 or 5 tanks then go to 32 or 40:1. You want more oil in for break in until things, well get broken in. Then you can run less oil which allows you essentially more power due to more available fuel to combust. Due to the low compression of these engines a lower octain is preferred.

A 4 cycle has more parts to lubricate as well as many passages for the oil to travel requiring more oil. A 2 cycle uses oil in the fuel to continually add fresh oil throughout the intake, combustion and exhaust cycles.

Attached is a quick chart for oil mix ratios.

matt167 · #3 07-11-2009, 10:41 AM

Yea, I put the 16:1 in my bike as the manufactures suggestion for break in.. and it just has that cloud of smoke that tells you it's got way to much.. next tank will be 20:1. and I might drain this out and run it in my weedeater, just diluted ( I never measure it 4 my weedeater, just go by color )

donuts31 · #4 07-11-2009, 02:43 PM

32:1 from day one with no lubrication failures in many many miles.

joeblow · #5 07-15-2009, 06:07 PM

I have some two stroke universal oil that says it is so high tech it replaces all mix ratios with 2.6 oz per gal. should I call their bluff and use the appropriate amount? I also have some 10w-40 motorcycle oil, is that better or worse to use in a 2-t engine?

Finfan · #6 07-16-2009, 12:08 AM

I think the 16:1 number comes from less developed countries where they use cruder types of oil for the mix (think non-detergent 30 weight). I used 20:1 with fossil oil for the first 2 gallons, 25:1 with fossil oil for the second 2 gallons and then went to 30:1 with a good quality synthetic oil. The theory is that the fossil oil doesn't reduce friction as much and allows the engine to wear in properly. Then after it is broken in you switch to the synthetic oil that reduces further wear. Just what I've picked up hanging around here.

crash vester · #7 08-28-2011, 08:36 PM

I used 16:1 for my bikes for a long time. Then I droped only to 18;1 I have to carry a spare plug with me all the time, and I use it. Think I will drop my mix a little more...Thanks

mapbike · #8 08-28-2011, 10:12 PM

Quote:

Originally Posted by crash vester

I used 16:1 for my bikes for a long time. Then I droped only to 18;1 I have to carry a spare plug with me all the time, and I use it. Think I will drop my mix a little more...Thanks

32:1 with a quality oil and it will run better and you will not be fouling those plugs as long as the carb is tuned correctly, you'll probably notice a nice power increase also.

Peace, map

Mozenrath · #9 08-29-2011, 03:39 AM

16:1 is excessive, but it's not really harmful to have extra oil. I ran 16:1 with weed eater oil at first, and I didn't get any smoke and it seemed to run fine. I did however switch to 24:1 on the next tank, and I'm still using 24:1 just because I don't know whether or not the engine is fully broken-in or not. I do want to get some opti-2 soon and try that out. I suspect it will run better with high-quality synthetic because not only will it require less oil but it really does seem like synthetic causes far less carbon buildup. I scraped some of the carbon off my piston last week, and after a few rides there was already more carbon in its place!

DuctTapedGoat · #10 08-29-2011, 04:37 AM

Quote:

Originally Posted by sofasurferlinux

My manual for chinese Jet Silver 80cc says to start with 16:1 and after breakin use 20:1. They are saying to go from more oil to less oil. The forums say to start with 20:1 or so and progress to 40 or 50:1, unless I and misreading something.

Can someone verify the proper mixes and explain what they do?
Do they very from motor to motor?
Does the octane rating in the gas matter or do we just use whats available?
And a little extra learning...Why does a car engine have massive amounts of oil being thrown all over everything but a 2 cycle only needs an amount that is virtually undetectable? They still work like **** and build up as much heat as ****.

16:1 is unnecessary. 24:1 is a good break in ratio, and after break in 32:1 is where ya wanna be.

The reason you want a higher amount of oil for break in is this.
Metal is pourous, as in it will soak up liquids. Cast iron cookware is a great example of this. In addition to wanting to "cure" all of the metal with the heavier oil mix, the extra oil in the mix will give you added compression - which helps your rings seat properly.

As far as the car engine - cars reuse oil, and you want a higher amount so that it lasts longer. As well, do a gas tank comparison to the 2.5L tanks on china motor bikes and you'll see there's not that much a difference.

And as far as "virtually undetectable". Go make some koolaid. It's a tiny little flavor packet, but wow does it do something to the entire mix. When you introduce oil to gasoline, the oil thins out across all the gasoline.