oil to gas ratio question for TOMOS

thedrifter /

I have a 07 sprint and premix. Tomos recommends a 50:1 ratio but a buddy says that its safer to use closer to a 40:1 ratio because all oils are different. I know the general rule is that its better to be rich than lean. I think im alittle lean already so maybe the extra oil will help extend my engine life. I shouldnt have any problems running a 40:1 right?

Re: oil to gas ratio question for TOMOS

John Joedicke /

Premix go for 40:1 with synthetic oils.

oil to gas ratio question for TOMOS

I don't seem to have any problem at 40:1 with regular 2-cycle oil, either.

Re: oil to gas ratio question for TOMOS

thedrifter /

which ratio will have the best engine life?

Re: oil to gas ratio question for TOMOS

mikey likes it /

0:0

Re: oil to gas ratio question for TOMOS

Synthetic oil mixed as Tomos suggested is ultimate. Cheaper oils

and too rich a mixture will rob power and cause deposits that clog

exhaust and make the rings stick. My Trials bike runs 80/1, some

racers run 100/1. Always use quality oil, dont skimp.

Re: oil to gas ratio question for TOMOS

Here's food for thought on this topic. This was explained to me by a knowledgeable source.

Adding oil to a premix outside of the recommended spec DOES NOT guarantee better performance of the lubricant nor does it offer any level of extended engine protection. The reason is that when you are adding oil, you are taking away fuel. For a given amount of air / fuel / oil mixture, there has to be a given percentage of air and fuel. About 14:1 air to fuel. If the fuel / oil ratio is modified, the amount of fuel per liquid ounce will change. Since the oil is not a combustion fuel, the air / fuel ratio will also change. If there is more fuel than ideal, the engine will run rich. If there is less fuel, it will run lean. As stated earlier, the additional oil WILL cause less fuel per stroke and result in a lean condition to some degree. The lean run condition is a huge problem on an air cooled two stroke engine because it will cause a higher operating temperature. This will lead to parts expanding more than designed which causes even MORE WEAR! Quite realistically, one could add enough oil to overheat the engine and seize it.

If a change of fuel / oil ratio is called for, one would need to calculate the different air / fuel ratio and re-jet the carburetor to compensate for the lost fuel. Sounds like a lot of work to me.

I would recommend using a good grade of oil and following the manufacturer's recommended ratio for this vehicle.

oil to gas ratio question for TOMOS

Yes, I use 40:1 and regular 2-cycle oil, and I run at full throttle a lot. No problems. Tomos says any oil with the TCW3 rating is OK.

Re: oil to gas ratio question for TOMOS

i ran 50-1 it ran so hot i couldn't even touch the side of the tranny ten minutes after i rode it threw a cap full of oil in and it ran a lot cooler so now i do 40-1

o its a fa 50 with out the oil injection. i got like 2 mph out of removing the oil injection.

Re: oil to gas ratio question for TOMOS

Let's see. You removed the oil injection and added oil to the fuel. The engine ran hot. You added MORE oil to the fuel and the engine ran cooler? Good for you, I guess.

Oh - Wait a minute. You had no idea what the oil ratio is supposed to be because you had an injection motor. So you GUESSED 50:1. Maybe bike ran hot because it was oil starved? You GUESSED again towards a more suitable ratio at 40:1. Congratulations on your engineering insight. Have you considered 32:1?

Did you bother to re-jet your carb while you were at it? You really need to do that, you know.

Your spark plug will confirm what I'm saying.

This has nothing to do with the original post which concerned altering the oil ratio on a designed premix engine.

Re: oil to gas ratio question for TOMOS

surprisingly my spark plug is a light brown color i was surprised as could be that its right. i have not tried 32-1 because it runs and it runs good so i don't muck with it. yeah i guessed but i am a lucky guesser with mechanics or at least with mopeds/nopeds the minibike and passport are a whole other story

Re: oil to gas ratio question for TOMOS

I have a really stupid question so please bear with me...

what is the difference between Premix and 2 cycle oil? Is there a difference?

Re: oil to gas ratio question for TOMOS

Premix is a mixture of gasoline and two stroke oil. 40:1, 50:1 and other ratios refer to the amount of oil mixed in with the gas -- like, 40 parts gas and 1 part oil, or 50 parts gas and one part oil, etc. If you have an oil injector (many newer Tomoses do) then that mixes the oil into the gas for you, so you don't need to premix. If you don't have an oil injector or it's disabled/removed, you mix the gas and oil, then pour that into your gas tank, then ride.

Re: oil to gas ratio question for TOMOS

so if i'm understanding you correctly, when I buy a bottle of premix I can pour the whole thing directly into the gas tank and that's the fuel? Sorry, im a total fucking noob in this regard. I never used premix on my old spree's.

Also, the premix doesn't smell like gas...

Re: oil to gas ratio question for TOMOS

premix is a technique

Re: oil to gas ratio question for TOMOS

When you buy a bottle of oil and you mix it with your gas, what you have is premix. "To premix" is the act of mixing the oil and fuel before putting it in the tank, and "premix" is the oil and gas mixture. Generally speaking, you shouldn't dump the whole bottle of oil into your gas tank because the ratio of fuel to oil is important. A 50:1 mixture is about 2.6 oz for every gallon of fuel. So, if you dump 8 oz into a 3/4 gallon tank, you're going to have an insane amount of oil running through your engine (lots and lots of smoke, if it will run at all). Sometimes you can buy little bottles of two stroke oil for lawnmowers and stuff, and they're measured out to be for certain ratios, like 40:1 and 50:1. If you've got one of those small bottles (usually only 2.5-3oz in a bottle) then you could dump that whole thing in your tank, but most moped tanks don't hold a full gallon, so you wouldn't even need the whole bottle.

Does this help at all?

I see on your profile that you have an '06 Streetmate. As far as I know, those have oil injectors. Did you disable it or something? You shouldn't need to premix unless your oil injector is out of commission.

Re: oil to gas ratio question for TOMOS

I think he is refering to the bottle like motul 800 which states premix and 710 which states injector. Use the injector stuff for your bike if it is still injected. You can use either if you are premixing fuel.

Re: oil to gas ratio question for TOMOS

yeah. The bottle says premix on it which confused me.

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