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

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 ****.

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.

Attached Files

Premix Ratio.pdf (18.9 KB, 22 views)

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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 )

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

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?

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.

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