How much 2 stroke oil should I run in my dirt bike?

[Sandblaster]

I have had several customers ask me, "How much 2 stroke oil should I run in my dirt bike?"
Another that is very similar is "What ratio for 2 stroke oil should I run in my dirt bike?"
Basically they are asking the same thing.
The first answer I give is, "What does your manual say?".
While 40:1 is generally considered safe, you should always use whatever your bike manufacture recommends.
I have used 40:1 for several decades with no problems.
Many companies such as LA sleeve recommend 32:1 only for break in.
So, what does 40:1 mean?
What this means is 40 parts of gasoline to 1 part of 2 stroke oil.
It does not matter what unit of measurement you want to use, Gallons, quarts, liters, or ounces, as long as you use the same unit of measurement for both the oil and the gas
Since we are in the USA we will use ounces.
Let's break this down.
There are 128 ounces per 1 gallon.
If we take 128 ounces and divide by 40 we get 3.2 ounces.
So:
3.2 ounces of 2 stroke oil per 1 gallon of gasoline = 40:1
6.4 ounces of 2 stroke oil per 2 gallons of gasoline = 40:1
9.6 ounces of 2 stroke oil per 3 gallons of gasoline = 40:1
12.8 ounces of 2 stroke oil per 4 gallons of gasoline = 40:1
16 ounces of 2 stroke oil per 5 gallons of gasoline = 40:1



Lets say that we we want to use 32:1 for breaking in a new engine.
If we take 128 ounces and divide by 32 we get 4 ounces.
So:
4 ounces of 2 stroke oil per 1 gallon of gasoline = 32:1
8 ounces of 2 stroke oil per 2 gallons of gasoline = 32:1
12 ounces of 2 stroke oil per 3 gallons of gasoline = 32:1
16 ounces of 2 stroke oil per 4 gallons of gasoline = 32:1
20 ounces of 2 stroke oil per 5 gallons of gasoline = 32:1



Now lets say that you like living on the edge and want to run 50:1
If we take 128 ounces and divide by 50 we get 2.56 ounces.
So:
2.56 ounces of 2 stroke oil per 1 gallon of gasoline = 50:1
5.12 ounces of 2 stroke oil per 2 gallons of gasoline = 50:1
7.68 ounces of 2 stroke oil per 3 gallons of gasoline = 50:1
10.24 ounces of 2 stroke oil per 4 gallons of gasoline = 50:1
12.8 ounces of 2 stroke oil per 5 gallons of gasoline = 50:1
15.36 ounces of 2 stroke oil per 6 gallons of gasoline = 50:1



Remember, ALWAYS consult with your bike manufacture and use what they recommend.
If you have any question or would like to add further information, feel free.
Thanks!
SB

[Christopher]

Could someone please recommend an oil to use? I have done some research but would prefer to get advice from someone I trust.

Christopher

[Sandblaster]

There are many good brands.
I use Motul 800 off road 2 stroke oil, but I have also used several others such as Maxima Super M 2 stroke oil, Spectro Golden 2-Cycle Semi-Synthetic, Pro Honda HP2 2-Stroke Racing Oil, Red Line 2-Stroke Racing Motor Oil, and Maxima Castor 927 - 2 Stroke Oil...

All are good.
If I had to switch right now I'd go back to Maxima Castor 927 - 2 Stroke Oil.
If I was going to experiment I would try Royal Purple 2 Stroke Oil.

If you ask 10 different guys you can get 10 different answers, and probably start a fight
Whatever you use mix it 40:1 (Another possible fight) and ride it

[Christopher]

Thanks Sandblaster.

Since I'm going to try Royal Purple 10-W40, I'll go ahead and try their 2 Cycle oil as well.

[Friar-Tuck]

Well put S.B.
Along with those oils, I tried Blue Marble (the guys up here use in their Bass Boats), and Polaris syn (power valve/ snowmobiles).
The only other thing that comes to mind is that I always have the guys use non-syn for break-in of their newly rebuilt top end, to get (I think) a good ring/cyl seal. (Caution! that is purely my speculation I have no data to prove /dis prove the break-in stuff)
Thanks for taking the time to write all that up S.B.
Tuck\o/
This is the only place I found something on how the oil/fuel migrates through an engine.
http://www.maximausa.com/pdf/Oil%20Migr ... 0Sheet.pdf

[Sandblaster]

Christopher, let me now how you like the Royal Purple...

Tuck, excellent article...
You do the same thing for so many years, not having any real validation as to why it works... Then suddenly your eyes are opened

On the break in, yes, we would prefer to use a non synthetic, however, your engine will break in just fine on a fully synthetic but it increases the break in time.
So if your in a hurry... Non synthetic to break it in.

Here is the info that Tuck posted... but you don't have to click on the link to see it...

oil chart 1.JPG (150.17 KiB) Viewed 17757 times

oil chart 2.JPG (137.97 KiB) Viewed 17757 times

[Christopher]

Interesting, based on the information above it seems that they recommend a 40:1 for 500cc motocross/enduro.

That goes against what Sandblaster told me, 32:1.

[Sandblaster]

Well... you won't hurt it running 32:1 as long as you are jetted correctly..
But here is what I said above:

Whatever you use mix it 40:1 (Another possible fight) and ride it

20+ years ago everything I rode was mixed 32:1
Everything in the last 20 years has been 40:1

I have never had a engine failure due to oil starvation.

[Christopher]

Wow, good job Chris. Clearly I can't count on my memory for anything. I didn't re-read what you had written previously. Thanks for correcting me.

[Sandblaster]

Oh man, no worries.. With so many facts and figures out there it's a wonder I can keep anything straight which is why I had to double check myself... Sometimes my mind thinks one thing and my fingers type something else