Two-stroke mixes

[dangerous]

I run my race bikes at a 30-1 mix thats 30ml oil to 1 liter of petrol (same as the RS125 GP bikes)... now my work mate has just picked up a mid 90's CR250 and the owner told him to run a 50-1 mix, now by me thats a lot of oil asuming its 50ml oil to 1 liter of petrol... but my work mate reckons he ment 50 liters of petrol to 1 liter of oil.

So question to you off roaders... whats the correct mix for a CR250??? :scooter:

[k14]

I run my race bikes at a 30-1 mix thats 30ml oil to 1 liter of petrol (same as the RS125 GP bikes)... now my work mate has just picked up a mid 90's CR250 and the owner told him to run a 50-1 mix, now by me thats a lot of oil asuming its 50ml oil to 1 liter of petrol... but my work mate reckons he ment 50 liters of petrol to 1 liter of oil.

So question to you off roaders... whats the correct mix for a CR250??? :scooter:
Roflmao, maths was not your strong point at school was it?

30:1 is actually 33mls per 1 litre of petrol. The ratio stands for 30 litres of petrol and 1 litre of oil. So if you do the maths you divide 1 by 30, and you get 0.033333. Now this means for every unit of petrol you put in 0.033333 units of oil. Thus if you have 1000mls of petrol (1 litre) you put in 1000 times 0.03333 of oil, which comes out at 33mls.

For 50:1 the number is 20mls of oil per litre of petrol. So it is actually leaner than 30:1.

When I'm doing the rs I normally put in 3 litres a pop and that means I use 100ml of oil. Easiest way to do it I reckon.

Now do you understand that or do I need to go through it again?

P.S. Have nfi about CR250 mix.

[laRIKin]

Roflmao, maths was not your strong point at school was it?

Hard luck D, at least you did seize a motor like some poor miss guided guys have.
A lot of people get it wrong.

[stify]

duno if it's any help but ran my cr250 powered kart (95 mtr) on a 32 to 1 mix, the engine was pretty much at peak load due to nature of kart racing, never had a problem with the engine

[cheese]

32:1 is all teh bikes factory reccomended spec. most people run 40:1. 50:1 is safe with good oils.

[laRIKin]

I think your mistake is that you looked at it as a measurement.
It is not a measurement it is a ratio, that is so many parts to so many parts.

Like a ratio of 2:1 is 2 cups, litres or gallons to 1 cup, litre or gallon.
So you end up with 3 cups, liters or gallons.

Here is a chart that may be use full.

http://www.rctek.com/pdf/fuel_to_oil_ratio_chart.pdf

[laRIKin]

32:1 is all teh bikes factory reccomended spec. most people run 40:1. 50:1 is safe with good oils.

I agree, you must look at what the bike manufacture says and what the oil manufacture says and the type of riding you are doing.
A MX bike is only under full power for a short time compared to a road racing bike, so you must factor that in as well.

Most good 2T oil do have a recommended ratio on the bottle for both on and off road bikes.

Oil threads are like.:brick: :brick: :brick:

[dangerous]

Roflmao, maths was not your strong point at school was it?
Na it wasnt, spelling was aye :Punk:

Thanks to all for setting me right, think I might add a little more oil into my brews from now on, and I'll pass on the info to my work mate, cheers ta :rockon: