As the Engine Turns!

MrLarkins

HS Math Teacher
Jun 17, 2008
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Arkansas
With the proper oil/gas mixture, your engine should hum nicely. But what does it sound like (or act like) when there is too much oil in the mixture or too little?
 

jasonh

New Member
Jun 23, 2008
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With too much oil you'll probably have some smoke coming out of the exhaust and it just won't run "right." More oil = less fuel per intake quantity = motor running lean.

Not enough oil...it'll be running richer, and if you really don't have enough oil, something is going to break eventually.
 

MrLarkins

HS Math Teacher
Jun 17, 2008
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Arkansas
i can't get the mixture just right...i think i got too much oil in the gas
no real power like before and top speed is reduced...and yes, i see smoke in exhaust as well as traces of oil near exhaust port...

i mixed 4 oz of Golden Specter with 1 gallon of gas (i hope it was 1 gallon)
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
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32:1 is O.K. and definitely not too rich on the oil....
I would have a look at the plug and see how it reads. If you are using a good 2 stroke oil, especially a synthetic, you should see no smoke, except maybe a little on start up.

Something else is amiss.
 

MrLarkins

HS Math Teacher
Jun 17, 2008
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Arkansas
like i said earlier, it is Golden Specter 2 stroke oil and is suppose to be really good. 32:1 ratio and I do see smoke (at full throttle)
 

Dave31

Moderator
Staff member
Mar 1, 2008
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Aztlán, Arizona
I run full synthetic, my engine will smoke a little at start up and a little when I stop at a light for a second or two.

I would pull your plug and take a good look at it...this will give you an ideal of your air/fuel mixture.
 

jasonh

New Member
Jun 23, 2008
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I run Valvoline at 32:1 and I only get smoke when I start it up with a bit too much choke. After that, there is no smoke whatsoever.

What does the plug look like? If it's black it sounds like you're still running really rich. You may have to solder and redrill your jet or get a new one, since you're on the top notch already...
 

MrLarkins

HS Math Teacher
Jun 17, 2008
487
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Arkansas
i thinned the gas/oil mix out a bit...i added .4 gallons to what was already mixed. It runs better and doesn't smoke any more.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
235
63
up north now
I'm thinking you were about .4 gallons short of one gallon when you mixed it before, rendering the mix at 16:1- smokey territory.
 

MrLarkins

HS Math Teacher
Jun 17, 2008
487
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Arkansas
well, my gas tank is 1.4 gallons, and i filled it to 1 gallon and mixed in the oil...smokey...so i filled the gas tank up full...another .4 gallons.
 

eDJ

Member
Jul 8, 2008
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Wayne National Forest
Just by way of suggestion, if you visit a dollar store you can probably find a bartenders measure there. It's like two small cups joined together at their bottoms. The larger is 1 1/2 ounce and the other is 1 ounce. (a jigger & pony in bartending lingo) Then if you find an empty 1 liter water bottle you can scale down your test mixes. 1 liter is roughly a quart. You can also use a 2 liter soda bottle later when you get the mix ratio you like. Thus you're mixing 1/4 and 1/2 gallon quantities using the bartenders measure and bottles. Now you can mix small experimental quantities till you get it right for your bike. Run the different mixes and read your spark plugs. Do this first.

But get yourself some measuring tools to mix with, a couple or three new spark plugs to use for testing and take your test mix and plugs and tools out to an open stretch of road where you can run all out for a few miles without interuption run test your bike. Then quickly shut down the engine (kill switch) pull over and let the engine cool enough that you can pull the plug and read the color. If you have a friend who can follow you in a car or whatever they can observe your exhaust for smoke etc.

It's hard to find a site that details reading 2 stroke plugs it seems. If your plugs are wet and black you are too rich with oil and fuel. You don't need a photo to know that.

This view is of plugs from a 2 stroke engine. To the left is an acceptalbe plug
and to the right is a good running plug. I drew some black lines on the ground electrode to try and better define it from the center electrode.



These three plugs may be acceptable for a 4 cycle engine but would be far too lean and hot for a 2 stroke engine. If you pulled these out of a 2 stroke it would be a sign that you need to enrichen your carb or check your ignition to see if the point gap and timing degrees BTDC are set properly. Plugs that look like this could signal failure, perhaps burn a hole in your piston etc.



Reading plugs in any engine is one of the skills any engine tuner should learn early. There's plenty of info from plug manufacturers for 4 cycle plugs
such as NGK's site with FAQ's.

Frequently Asked Questions