Two Stroke Premix Ratio

[Dell30rb]

What ratio do you run? I like to use 32:1 mx2t.

Vote ye people!

[Keetoman393]

I use to run 100:1 in my Trials bikes.

[Rockey]

Ohhhhhh Ren can I be the oil expert!!! Can I, Can I, Can I?!?!?! PLEASE!!!!!

I run MX2T at 24:1 in the 125. I like my bearings to last.

[Madman393]

I have been running Klotz 80/20 castor at 44:1. KX500 so I think that I can stand to run a little less than I would with a 125 or a 250 turning less revs.

[Dell30rb]

Rockey.. you only have one bearing?

[KTM250rm393]

What my mechanic who has been racing for 20 years and now all his sons race either 4 wheelers or motocross.

High reving engines like 125's need a mixture of 32:1 while lower reving 2 strokes can work on anything from 32:1 to 50:1. It really depends on how you got your bike jetted. You can jet your bike to run at 32:1, 40:1, 50:1, or even 60:1 with no problems.

[mat bow]

I always ran 40-1 ratio when i had 2 strokes, big bore or small didn't matter never had a problem with any of them.And i never stayed with the same oil.A friend uses outboard motor oil and has had no problems in years of use! Just my thoughts on the subject.

[Dell30rb]

I was thinking about using outboard motor oil. We run full synthetic motor oil in our outboard, and its only 15 bucks a gallon
I may end up using it, If I do i will mix at 20:1 or something like it just to be sure.

[bluebyu]

I RUN 40-1 IN MY CR250.But used to run 32-1 in my old 500.

[mx757]

i currently run around 36:1 roughly. i want to start buying that 100:1 amsoil racing premix and run it at around 80:1

[Rockey]

Originally posted by dell30rb
I was thinking about using outboard motor oil. We run full synthetic motor oil in our outboard, and its only 15 bucks a gallon
I may end up using it, If I do i will mix at 20:1 or something like it just to be sure.

Don't do it. First off, your jetting is going to be way lean at 20:1, the bike will run all screwey. The component makeup of a TC-W3 outboard oil (the current outboard oil classification) is NOT designed for a broad, constantly changing engine speed. It is optimized for a more constant engine speed, like a boat experiences. Also, an outboard motor doesn't churn 10,000 rpm like your CR125 does. People often say that there are racing outboard motors which rev to 10,000, but they aren't running ordinary outboard oils. Definetly more than $15 a gallon. MX2T is a deal in itself, stick with it.

MX997, don't run that little oil in your mix. I just don't believe that is enough oil, even if the oil protects very good. Imagine its protection at 32:1 or 40:1.

Ren, be a pal and exercise your moderating privledges, and give my bearing an "s"

[KTM250rm393]

I agree with Rockey,

Outboard 2 stroke oil does not have the same lubrication capabilitys as for dirtbikes.

Same as air cooled 2 stroke oil will not work properly in a water-cooled engine.

For the cost of a trashed engine (600-800) its not worth it to be skimping on your two-stroke oil.

If you need to buy something more reasonable, go with Mobil-1 MX2T full synthetic at 3.49 a pint.

[Dell30rb]

I fixed your bearing.

Anywho, the fully synthetic does not wear the tc-w3 tag, and is much more expensive than tc-w3 oils. (Reg. oil is around 8 bucks a gallon)
On the applications list, it lists dirtbikes snowmobiles, and, of course "high output outboard engines".

I'm still not sure what to think. Mabye I will try it after the current top end gets old, and needs replacing anyway.

20:1 shouldnt be too bad, my bike's jetting is off enough as-is. (way rich)

[mx757]

running 20:1 is just going to make the bike more rich. thats only 20 parts gas for 1 part oil as opposed to 40 parts gas to 1 part oil thus making 20:1 way more rich.

[Rockey]

20:1 will richen the oil to fuel ratio, but it will LEAN the jetting as you are lessening the amount of fuel by adding more oil. When we say lean and rich, we are talking about jetting. Don't confuse the terms, because that confuses people

[mx757]

yeah but when the plug is covered in oil the bike is rich.

[Madman393]

Originally posted by Rockey
20:1 will richen the oil to fuel ratio, but it will LEAN the jetting as you are lessening the amount of fuel by adding more oil. When we say lean and rich, we are talking about jetting. Don't confuse the terms, because that confuses people

20:1 will result in less fuel to air ratio, thus making it run leaner, as the oil is displacing the gas that would usually be there.

Inverse relationship-->Decrease the ratio, increase the oil, decrease the gas consumed per cycle-->leans the mixture

Conversely, Increasing the ratio richens the mixture.

[2fun]

Originally posted by Rockey
20:1 will richen the oil to fuel ratio, but it will LEAN the jetting as you are lessening the amount of fuel by adding more oil. When we say lean and rich, we are talking about jetting. Don't confuse the terms, because that confuses people

Rocky and Guidster are "spot on" on this subject.
Using more oil will richen the oil to fuel mixture, but will LEAN out the fuel to air mixture.

Remember, fuel is not only the ignition source, but also a cooling source. Too little oil OR fuel will cause things to heat up, and or run poorly.

[MotoMan]

Yep, our "Supersonic" friend hit it right on the head.

Darn it 2fun, how am I gonna go about getting my Regulator status back?

[Woody_393]

I personally don't mix any stinking fuel... But I voted 40:1 for the heck of it. Just fill and ride. :