Gas Oil Mixture how does this effect proformance

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Keef B

New Member
Dec 30, 2015
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northridge
Hey Fellas,

Im running a 2 stroke with a jake diamond head, ported, SHA dellarto clone carb. Im curious to know for my break-in period I was told to run about 8oz to a gallon mixture. Then after break-in to run about 6oz to a gallon mixture. Now I've been told by some that's heavy on the oil side and some say its fine wanted to get some insight on this??

HAPPY 2016!!!
 
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Keef B

New Member
Dec 30, 2015
19
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0
northridge
Thanks Chaz,

I thought it was kind of heavy, plus it could foul up my spark so my next tank I'm going to lower my oil mixture and see how it effects performance.
 
Chaz

Chaz

Well-Known Member
Jun 3, 2012
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Vancouver, British Columbia
You're welcome, Keef. That heavy mix can definitely foul plugs and clog up your muffler. The manufacturers advise the heavy mix to protect the warranty and avoid trouble from seized pistons etc. it's overkill.

I would suggest you read through some of the threads regarding break in procedures as well. Read a bunch and then come to your own conclusion as to where you feel comfortable. Some very experienced builders even suggest to break in with the final ratio that you plan to run your engine with. The choice is yours but make sure your air/fuel mix is not too lean. Check your plug colour to see what's happening in the cylinder.
 
Bikeguy Joe

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
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Think of it this way as well- @40:1 you have more than twice as much gasoline in the gas/oil mix, and that means a 'richer' carb setting.
 
2door

2door

Moderator
Staff member
Sep 15, 2008
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Littleton, Colorado
Bikeguy Joe said:
Think of it this way as well- @40:1 you have more than twice as much gasoline in the gas/oil mix, and that means a 'richer' carb setting.
Click to expand...
Which is all too often overlooked when trying to tune a carburetor.

It's very simple. Oil doesn't burn therefore whatever oil is in the mix, if decreased, means more of the mix is gasoline. More gas means a richer fuel to air mix. Decrease the amount of oil and you'll need to decrease the mount of fuel to the fuel/air mix for an effecient burn.

This is where folks get in trouble running the exotic 100:1 oils. To get the engine to run right they go lean on the fuel to air mix but often overdo it and end up with a damaged engine. Then they blame it on the oil.
2door just shakes his head and walks away.

Tom
 
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