different way to change fuel/air mix?

Prasinos · Dec 7, 2009

So after losing my #65 jet i have been forced to run my bike a little rich untill i can get a replacement. I was thinking about using a mix of fuels to change your mixture.

If you wanted to go leaner i woule think that mixing Kerosene or diesel into your gasoline would make the mixture leaner because they dont evaporate or flow as easily.

Going richer you could mix alcohol with your gas.

If you guys agree that any of these might work it would also allow you to try out going leaner or richer before buying a new jet or drilling out your stock one......

camlifter · Dec 7, 2009

i've mixed E-85 with 87 octane before, it makes for a leaner jetting, start with small amounts of e85 and work it up till you get a nice tan plug. methanal is also going to make it leaner, but also draws water into it so you would have to use it up fast. diesel and kerosene are not going to burn well mixed with gas in one of these engines. using a smaller jet is the wisest move, but the e85 mix gives a higher octane, home made race gas if your jetted for it.

toker_ace · Dec 9, 2009

remove your idle screw. My bikes run much better without the screw altogether.

BarelyAWake · Dec 9, 2009

Sorry, but that's not great advice toker, the idle set screw does actually have a job to do, it would also cause some bikes to run way too lean, and ofc there's the chance that water/crud can get sucked in through the hole.

If yer runnin' so rich as to need that much of an air leak to compensate - there's problems with yer set up you need to attend to.

toker_ace · Dec 9, 2009

To lean out my mixture do i move the c clip up or down?

BarelyAWake · Dec 9, 2009

Up FTW

Bikeguy Joe · Dec 9, 2009

Mixing diesel would not be a good idea either.
If you must change your mixture some other way than the correct way, change the amount of oil you use. A 24:1 mixture has half the gasoline that a 50:1 mixture does. (don't get crazy on me math freaks...).
Sooo, using that you can adfjust your fuel to air ratio quite a bit.

Other fine tuning of the mixtures can be done by adjusting the float level up or down, and the amount of back pressure and intake restriction can also be tweaked a bit.
Have fun, watch your plug for changes and don't run it too lean.

Prasinos · Dec 9, 2009

but going from 24:1 to 50:1 only increases your gas about one fiftieth (23/24)-(49/50)=.0216. Im talking about changing it more than that. Also, oil is somewhat expensive and makes more smoke and carbon buildup. I know there are military two strokes that run on diesle and i know of others that run on kerosene. First of all, if i wanted to try it, is kerosene completely soluble in gasoline?

Bikeguy Joe · Dec 9, 2009

Like I said, don't freak on me math freaks, but isn't 50 parts gas to one part oil twice as much as 25 parts gas to one part oil? That's a huge difference.

Bikeguy Joe · Dec 9, 2009

Those military bikes that run on kerosine are called diesels, or multi fuel engines, and are not anything like our engines.

george_n_texas · Dec 9, 2009

I am not recommending it but the hottest fuel I know of is coleman fuel. I'd be real careful if you try it wear some asbestos shorts LOL

If we see you with no eyebrows we'll understand.

Prasinos · Dec 9, 2009

Bikeguy Joe said:
Like I said, don't freak on me math freaks, but isn't 50 parts gas to one part oil twice as much as 25 parts gas to one part oil? That's a huge difference.

no because that's comparing gas to oil not gas to gas. If you mix a gallon of 50:1, it is going to have 50 units of gas in every 51 units mix, if you mix a gallon of 24:1, its going to have 24units gas in every 25 units of mix so 50/51 = 98% gasoline in 50:1 while 24/25 = 96% gasoline, so you are really only changing the amount of fuel by 2 percent. Even if you go to 16:1 its still 94% gas, so using more or less oil is really just for very fine tuning.

Also, paraffin lamp oil?

And does anyone have an reason they can back up to why i shouldn't at least try this?

Venice Motor Bikes · Dec 9, 2009

Yes you can actually lean out the mix by adding more oil.
My GF's bike (purple rain) was running perfect on the break in mix, (24:1)
after I switched it to 32:1, it was running too rich! (4 stroking)
I don't recommend using too much oil in the gas because it can foul the plug.

Prasinos · Dec 9, 2009

no offense fellas but it seems like everyone always wants to tell you something that doesent apply to the thread.

I am well aware of the fact that adding oil leans the mixture.

However, my question is, can you mix your gas with something else to lean/richen the mix?

Sorry to be so frank but 13 posts in and noone has really given me an answer with a reason why.

Venice Motor Bikes · Dec 9, 2009

Sorry for trying to help.... I won't do it again.

Also, I think Camlifter DID answer your question in the very first post.

george_n_texas · Dec 9, 2009

I guess I'm confused I thought lean was more fuel with less oxygen. I don't want to be rude but how the heck did you loose the jet in the first place?

Venice Motor Bikes · Dec 9, 2009

george_n_texas said:
I guess I'm confused I thought lean was more fuel with less oxygen. I don't want to be rude but how the heck did you loose the jet in the first place?

'Lean' means too little fuel (jet is too small/ white or grey plug)
'Rich'....... too much fuel......... (black (maybe wet) plug)

george_n_texas · Dec 9, 2009

Well now that I understand the equation better I'd say use rubbing alcohol that surely has less octane...the clear stuff. Worse thing that could happen is to have to drain the tank. Be hit and miss anything you try I wouldn't try reinventing the wheel I'd just wait for the jet...OTOH you could solder and drill the one you have there is a string on how to do that. http://motorbicycling.com/f13/stock-carb-mod-1494.html

tyrslider · Dec 9, 2009

camlifter said:
i've mixed E-85 with 87 octane before, it makes for a leaner jetting,...but the e85 mix gives a higher octane, home made race gas if your jetted for it.

I think you mean lower octane don't you? E-85 is Oxygenated 85 Octane? If it has the affect of leaning it out it is comparable to lower octane gas. Higher octane gas burns slower, more controlled and requires more compression to burn properly! So it does run better leaned out but it's not "race" gas it's a properly "tuned" fuel delivery sytem.

2 strokes are typically low compression motors and don't require high octane gas. They do love to run lean though! That is, until they sieze!

Toker, the needle only affects fuel mixture from about 1/4-1/2 throttle. Idle jet (circuit) below 1/4 and main jet above 1/2 throttle.

Don't mean to be nit picky but gasoline properties are widely misunderstood and the source of much confusion.

P.S. If you want to tune your engine, learn how to tune your engine! I think it kind of backward to look for a chemical mixture to solve your engines running issues.

george_n_texas · Dec 9, 2009

I almost forgot there is one more sure way to change the air fuel mix...move to a different elevation.

different way to change fuel/air mix?

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