How To Guide Oil to Gas Ratio Help!!!!!

StrangeTechnician9

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May 8, 2012
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27
So... How do you determine problems from using the wrong ratio?

For example, if you got the math wrong and mix 6.4 oz of oil to 2.3 gallons of gas while breaking in the engine. That makes it a litte higher than normal after break in ratio. Now that's improperly broke in, I dont know if I should go add a little extra oil or not.

I shoulda bought that self measuring bottle of oil I found... If I had read this thread before filling up might have helped too.
 


Greg58

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Jun 3, 2012
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237
The higher oil ratio during break in is to help prevent undue wear on most engines, that is only a recommendation not a requirement. Some people use opti2 at 100/1 from the start, if your engine shows no sign of wear when looking in the plug hole or hasn't lost any power you should be ok.
 

HeadSmess

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May 17, 2010
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my personal theory on this "16:1 and 20:1" is that in the country these are manufactured in, and invariably sold in large quantities, the average guy on the bike is going to use any old engine oil, just like in every other country circa 50 years ago when these things where first designed...

all old 2strokes have these ridiculous oil ratios for the simple fact that good 2 stroke specific oil just didnt exist! better to run lots of it than sieze up! smoke? lets you know its running!

same for the low compression ratio...can run them on any old gunk lying around in a bottle that burns.


nowadays we have fancy scientists getting paid big bikkies to make betterer oils so we can run 100:1 ratios... all about that EPA stuff...
 

Fabian

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Sep 8, 2009
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my personal theory on this "16:1 and 20:1" is that in the country these are manufactured in, and invariably sold in large quantities, the average guy on the bike is going to use any old engine oil, just like in every other country circa 50 years ago when these things where first designed...

same for the low compression ratio...can run them on any old gunk lying around in a bottle that burns.
I agree.

at 16:1 you can throw any kind of oil into the fuel (so long as it will mix in the tank) and the engine will still operate and transport 'primary produce' to the market stalls.
 

Greg58

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Jun 3, 2012
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A lot of people think less oil is better because they think it will give them more power, what I have found to work for me is to find a ratio that doesn't smoke or leave oil dripping out of the exhaust pipe. Then I tune the carburetor for the best performance possible.
 

phil79

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Jul 5, 2013
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I did the 20:1 one thing when I 1st fired my engine for the 1st tank the manufacturer rec. 1 gallon I did half of that. I think its a little nuts if you ask me I had oil everywhere. I'm running 32:1 now and have gotten way better results however still a little smoke and oil leakage from the exhaust port. A small engine mechanic recommended amsoil said it was guaranteed to work in all two strokes 50:1 IDK if I exactly want to trust that or run my engine that lean any extra power and I would probably use it and blow the little motor. I am going to try a 40:1 ratio when I get the chance to ride again. I personally think 20:1 is a little bit much for two tanks i personally would recommend just one tank at 20:1.
 

Fabian

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Sep 8, 2009
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4,522
20:1 for heavy duty haulage at low speeds with the engine working it's guts out.

25:1 for any other mode of engine operation when running close to 100% duty cycle.


100: for :whistle:

Ummm, 100:1 for :whistle:

That's right, 100:1 is good for :whistle: purchasing replacement parts...
 

rogergendron

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Sep 2, 2013
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11
when i first bought my grubee gt5 i ran it at 16:1 like the manual said and thought that is way to lean and too much oil it will carbon up in a second. sure enough lol using the suplied oil and the recomended mix of 16:1 after i rode about 150 miles i took the motor apart for inspection ............ lolol lol lol 16:1 my but ! the whole top of the piston had a thick (for 150miles) layer of carbon and the cumbustion chamber on the head was crudded up and the cheap 3 prong spark plug was black as a cat and fould !!!! i knew i could get way more power from this thing if i modded it my own way.

i have no money but i have lots of tools so time for the...
FREE MODS !

so i took the cilynder and heaad off and gave the cilynder a good heavy port and polish, raised the exhaust about 3/16 and lowered the intake about 3/16 and widend bolth by 1/16 each side then decked it down a little with sandpaper and glass... then the piston i rounded the edges of it and made ramps for all the ports even the transfer ports effectively changing the timing ( if you look at the top of the piston now it has a 4 leaf clover pattern ground in it) and i cut a full 5/16 off the entire intake side of the piston skirt ! man its way lighter than before WAY lighter ! allowing for quicker rev's. along with the port time changes i made with the dremel i estimated it would be a lot better for mid to high rpm power.

the head i had to take a lot off because i ground a lot off the piston witch lowered the compression so i took .100 off the head and dremeled a new squish band in by hand then polished the chamber to a mirror finninsh and put in a nkg b5hs plug and made shure it did not hit the piston and it was in line with the intake port.

i also port matched the exhaust and intake by the way i am using the long intake ... the z one with a 2.5 in extention hose for addeed tourqe .

i installed a new set of rings after a slight honing of the cilynder (slight i said as i was scared the cheap chrome would flake just enough to put some honing marke back on there at 45s or so) and reasembled the motor. it has a lot of compression now way more than stock ! it tested at an average of 138psi !!!

i cut off the cheap crappy plug boot and just crimped a simple loop conector strait onto the plug wire and screw it onto the tip of the plug directly ( mutch better conection )

and since then i have been running my oil gas mix at 40:1 full synthetic ... i use promix at lowes or true fuel 40:1 premix

good god man after those FREE MODSmy motor feels like a whole new beast !!!! it is literaly 3 times more powerfull !!!! i can cruse comfortably at 30mph !!!!

after about 100 miles i tore down the top end to inspect its condition and wow is all i have to say ! running 40:1 full sythetic and 93 oct the combustion chamber looked spotless like a mirror still and the cilyender was spotless no signs of scratches or wear the piston was perfectly clean aside from the small brown spot where the spark plug was fireing and the plug looked like chocolate color but slightly darker than usual (probably because i was riding low rpms and going slow for a lil bit before shutting it off and tear down) the plug on normal inspection ... WOT then cut off looks perfect !!!

so my theroy is that these motor can run at 16:1 or 20:1 or 25:1 with regular oil but you will carbon the heck out of it and foul plugs like a mad man. also you wil never get the full potential out of the motor with so little gas in the mix and natural oil.
even in a bone stock motor i would recomend you run 32:1 to 40:1 and use full synthetic right out the box! even for break in that is how i broke in my new rings at 40:1 full synthetic and my engine has rediculous amounts of power compared to when it was stock and at 16:1.

so i tell everyone who ask me what i run ... 40:1 full synthetic 93 oct. i recomend that mix also to all who have a grubee gt5 if your stock compresion then use 87oct 40:1 if your high comp the 93oct 40:1
some higher grade better more well designed oils for motor crross race bike can be run at 50:1 to 75:1 but i personaly would never go over 50:1 on this type of engine as it does need significant lubrication ! the parts are cheaply made and tolerances are not to spec so pushing the limit of how little oil you can use... it is very stupid for sutch a tiny insignificant gain if there even is any .... i would rather run 40:1 full syn and know i am safley lubed and getting the proper amount of air fuel mix than run 16:1 and be lean and foul up my engine or 75:1 and be to rich and stressing all my bearings and every moving part with unnessasary heat and preasure

i also tried running it at 50:1 full syn with lucas oil upper cilynder lube added to the gas and the differance was neglegable i hardly noticed a thing and my plug looked like it was getting lighter in color and straying off from the good coco color i want so i swapped back to 40:1 and add a little (1oz) of lucas oil upper cilyender lube every other tank.


 
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