Fuel amd Oil Mixture

RedB66 · Feb 20, 2010

I was just watching a video on Youtube on the subject of setting the carb to run lean or more rich. Over the years there have been numerous threads and questions on this subject. So....heres one more... or two.

Wouldn't you have to be precise on your fuel to oil mixture? I for one mix my gas 1 gallon at a time using a gallon container and 2 cycle oil bottle with the 2oz. increments on the side.

Could lean or rich conditions be achieved by pouring what I think is a gallon of gas from my 5 gallon can and adding what I think is the correct amount of oil. How precise does it need to be? Is it an exact science?

If I check my plug and I notice it is running lean, could it be remedied by using more oil on the next batch. Or vice versa with rich conditions?

It makes sence to me that a consistant mix will rusult in consistant performance but, how much is it effected by being off the mark?

Venice Motor Bikes · Feb 20, 2010

I haven't had much of a problem with the mixture being a little off...

bairdco · Feb 20, 2010

i've got a two gallon can that's just slightly bigger than 2 gallons. seem like everytime i fill it up it costs $6.66.

so i get more or less 2 gallons, then dump in more or less 2 oz. of Opti 2 for a more or less 100:1 ratio, and shake it up.

i'm never 100% accurate, and my bike doesn't seem to notice the difference, and neither do i.

Gareth · Feb 21, 2010

Here is a good primer on tuning..

Carburetor Theory and Tuning :: Two Stroke Motocross

The more oil, the less gas = leaner mix.

Bikeguy Joe · Feb 21, 2010

Yes, you can adjust your mixture with the gas to oil ratio.

16:1 is twice as much oil as 32:1, so varying the ratio from 16-50:1 would be one way of "adjusting" the fuel mix to air ratio.

It does make a difference when you experiment, try it if you don't believe me.

Bikeguy Joe · Feb 21, 2010

RedB66 said:
If I check my plug and I notice it is running lean, could it be remedied by using more oil on the next batch. Or vice versa with rich conditions?

If it's lean, and you add MORE oil, you will get a grinding sound followed by silence.

More oil will make the mixture of fuel to air LEANER.

FileStyle · Feb 21, 2010

Bikeguy Joe said:
If it's lean, and you add MORE oil, you will get a grinding sound followed by silence.

More oil will make the mixture of fuel to air LEANER.

would'nt more oil make the mix rich instead of lean?
less oil would make it run lean! follwed by the grinding sound then silence.

Xiodinc · Feb 21, 2010

whats the best oil mixture after it is broken in?

BarelyAWake · Feb 22, 2010

FileStyle said:
would'nt more oil make the mix rich instead of lean?
less oil would make it run lean! follwed by the grinding sound then silence.

This again?

What joe's talkin about is gasoline & air mix - if you have more oil, you have less gasoline thus "lean"... less oil = more gasoline & "rich".

It's actually more complex than it sounds, by adjusting the mix via carb - your fuel air mix (fuel being both oil and gas) changes, by diddling around with your oil ratio - yer messing with the gasoline/air mix... it is actually a different thing.

How much of an effect too much oil (running lean on gasoline for the sake of lubrication) has on the potential for seizure... well... the jury is still out on that 'un but it'll defo lead to ignition woes

Bikeguy Joe · Feb 22, 2010

Somewhere between 32:1 and 40:1 is a good ratio once broken in. A lot of guys are running 50:1 synthetic with good results.

Yes, more oil in the gasoline to oil mix will make the engine run leaner fuel to air wise.
Too much oil is as bad (in a different way) than too little oil.
Too much oil will make a lot of carbon build up, sticking rings, plugging exhausts, ect. If it's waaay to much, you probably will not sieze your engine, right away, but it's best to be careful and mix you oil into your gasoline ACCURATELY.

There's no reason not to.

ZRTMWA · Feb 25, 2010

Bikeguy Joe said:
Somewhere between 32:1 and 40:1 is a good ratio once broken in. A lot of guys are running 50:1 synthetic with good results.

Yes, more oil in the gasoline to oil mix will make the engine run leaner fuel to air wise.
Too much oil is as bad (in a different way) than too little oil.
Too much oil will make a lot of carbon build up, sticking rings, plugging exhausts, ect. If it's waaay to much, you probably will not sieze your engine, right away, but it's best to be careful and mix you oil into your gasoline ACCURATELY.

There's no reason not to.

Very n00bish question but what ratio would you recommend befor it's broken in? I've heard 16:1 and 25:1. Also how long is break in time? I've heard 300ish miles for that.

stv1jzgte · Feb 26, 2010

ZRTMWA said:
Very n00bish question but what ratio would you recommend befor it's broken in? I've heard 16:1 and 25:1. Also how long is break in time? I've heard 300ish miles for that.

I installed a new gt5 on sunday i rode it to work all week (26km return trip) and to the shops halve a dozen times, i mixed a batch of 25:1 and have used about 3 litres of it, traveled 160km or 100miles!
She's broken in.
If you baby it, putt around and let it idle for extended periods yeh it could be 300miles. dont abuse it but dont be soft.

Bikeguy Joe · Feb 26, 2010

24:1 Ride your break in miles with various throttle amounts, and engine speed. Stay away from long down hill runs with the throttle closed. Other than that, if it doesn't break in the first 5 minutes, you aren't going to hurt it unless you idle for prolonged periods, or lug the engine down to slow. (bad for the bottom end).

ZRTMWA · Feb 26, 2010

Bikeguy Joe said:
24:1 Ride your break in miles with various throttle amounts, and engine speed. Stay away from long down hill runs with the throttle closed. Other than that, if it doesn't break in the first 5 minutes, you aren't going to hurt it unless you idle for prolonged periods, or lug the engine down to slow. (bad for the bottom end).

Thanks. I take it throttle closed means all the way off (not in use)? My driveway is a really big hill, guess I'll just have to walk it down. To start the motor, do you have to pedal around 3-5 mph or does the bike just have to be moving that fast? Thanks.

stv1jzgte · Feb 26, 2010

I dont pedal

>ScCruisin< · Feb 27, 2010

You wont have to walk your bike down your driveway, just hold the clutch in silly! And you dont have to be pedaling, just moving. I usually just get on my bike and give a little push then as i release the clutch i thrust my body forward then pull the clutch back in quickly after the engines running. This lets you start the engine easily at really low speeds, or even uphills.

Bikeguy Joe · Feb 27, 2010

If you are going to pedal start, I'd say a little faster like 10 mph. Once you get the bike broken in, and properly tuned, you may be able to use the above mentioned bump start methods as outlined above. One helpful thing when starting is to prime the carb with the "tickler button" (left side) and use not-quite-full choke.

If I were you, I'd use the long downhill driveway to start your bike, maybe no pedaling required.

ZRTMWA · Feb 27, 2010

>ScCruisin< said:
You wont have to walk your bike down your driveway, just hold the clutch in silly! And you dont have to be pedaling, just moving. I usually just get on my bike and give a little push then as i release the clutch i thrust my body forward then pull the clutch back in quickly after the engines running. This lets you start the engine easily at really low speeds, or even uphills.

I promise this will be my last n00bish question for a while. I would search but I don't know what words to use that would yield the right results.

Will riding my bike normally, without the engine running, hurt the engine in any way? I can't think that it would but I just want to be sure. Could I get some definitions for "clutch in", "clutch out", "throttle open", "throttle closed"? Again last n00b questions for a while. I completely new to all engines and their workings...

Thanks

bairdco · Feb 27, 2010

clutch in means lever pulled in, and the engine's drive is disengaged.
clutch out means lever released, and engine drive is engaged.
throttle open means twisting it to give it gas.
throttle closed means untwisted, engine idling.

riding the bike normally, you have to pull the clutch lever in, and you'll feel the slight drag as the motor chain spins, but it won't have any bad effect on the bike or the motor, it's just heavier, and not as fun.

bairdco · Feb 27, 2010

Bikeguy Joe said:
... but it's best to be careful and mix you oil into your gasoline ACCURATELY.

There's no reason not to.

so, when i ran out of gas yesterday and eyeballed some cheap chevron oil that comes in a black bottle with no markings, then added .46 gallons of 91 octane, not counting what spilled all over since my fuel inlet is too small and i had to use a paper funnel, is that considered "accurate?"

Fuel amd Oil Mixture

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