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Who do I believe when it comes to mix ratio?

My '06 Kawi book says 36:1 ratio but most all the oils that I am looking at say 50:1 ratio.

I am not running hard that much but I do let her breath heavy whenever possible.

Thanks for your input here.

Your Kawi manual states 36:1 ratio? Wonder why the change from older manuals (mine states 32:1) . . .

A 32:1 mix ratio has been used successfully in 2 strokes of our size for literally generations . . . I use Amsoil Interceptor and, despite the mfg directions for 50:1, I continue to use 32:1. Good stuff, that Amsoil.

Many on this site use 40:1 and claim ease of mix (16 oz bottle per 5 gallons).

At least one member experimented between 32:1 and 40:1 and found better performance at 40:1. (on his bike).

My take on this is that you're doing your job in protecting the engine whether you pick 32:1, 40:1, or somewhere within the range. Try a few different ratios and see if it makes a difference. Just use a quality 2-stroke oil.

40:1 is fine....Personally don't like 50:1, but in the woods, low RPM, and the fact that most people are jetted fat it won't hurt anything. With proper jetting 20:1 can be run while maintaing a foul-free spark plug, but that's REAL HARD to do while idling. Synthetic oils help a lot. Anywhere from 24-40:1 is my preference. More oil=more power so it all depends on how anal I want to jet and the terrain. Wide open terrain 24:1, and will more than likely be left over 12:1 C-12 castor/syn blend from my kart cut in half w/ pump gas (oh the smell ).....Tight terrain, 40:1. On any given day combined with the fact that I've hardly been riding lately I have to jet before riding regardless.

The main word I believe is whatever ratio, jet the bike accordingly

Hey Fuzzy; what do you mean "More oil=more power "?

More oil = less gasoline in the charge going to the engine, so I've always thought that More Oil = Less gas=less power.

Also, more oil =more viscosity to the fuel =leaner feed to the motor unless the jetting is compensated.

Educate me

More oil = better ring sealing = more power

but I'm sure there's a point where those effects you mention start to impact power more so than stuff like ring sealing

If only we had a couple of free months to dial in the huge variety of parameters for optimal performance . . . but then the temp and humidity factors would change!!

I knew I knew that. It's just that I forgot it. Thanks for the reminder. I'm going to test that out. I'll start with a 50:1 mix, increase the oil to 32:1 and see if it's a felt increase in power. My butt is pretty educated.

I must confess that my "more oil = better ring sealing = more power" comment is info I'm repeating; i.e. I can't say that's true through personal experience.

I'll bet most people wouldn't detect the difference, if they weren't looking, between ratios 32:1 and 40:1.

It'll be interesting to see what your butt has to say . . .

My father ran an '81 Suzuki PE250 for 17 years at 55:1 on the stock piston... As long as it's synthetic...

More oil = leaner running bike. Less gas is going through the jets. Many a rider has got that backwards and thought they could remedy a rich running bike by reducing the oil in the pre-mix. Problems ensued.

More oil = more power.

McCulloch is often cited for that fact. They found that, jetting compensated, the more oil used, the more power..to the point of plug foul. At SOME point, a given ignition system isn't going to be able to spark a charge that has a 'lot' of oil in it.

There is a published ASME white paper around that says all that.

Obviously there isn't going to be a lot of riding going on with a 2:1 ratio and a two gallon fuel tank.

I think I've found it before on the web...but I'm not so lucky now.

The rule of thumb I've read is: Run what the mfg specs..unless the OIL mfg says different. That's for starters. After that...run what works.

I've run 32:1 in my KDX..jetting compensated. It didn't work to my satisfaction. On the other hand, 32:1 in my Banshee is considerably better running than 40:1.

Ease of mix? A pint in five gallons for 40:...in four gallons for 32: Easy shmeasy.

canyncarvr wrote: Ease of mix? A pint in five gallons for 40:...in four gallons for 32: Easy shmeasy.

40:1 is easier if you want to fill a 5-gallon jug . . .

RE: 32:1 not good enough in the KDX - guess I'll just have to try 40:1 some day and see what I'm missing.

canyncarvr wrote: Ease of mix? A pint in five gallons for 40:...in four gallons for 32: Easy shmeasy.

40:1 is easier if you want to fill a 5-gallon jug per the easy shmeasy crowd.

RE: 32:1 not good enough in the KDX - guess I'll just have to try 40:1 some day and see what I'm missing. I'd love to be pleasantly surprised . . . and I gotta put some of that toluene sitting on the shelf in my mix as well. As soon as I can ride.

Maybe I'll spike Jeb Jr's RM premix with it and see what he thinks

paceyman wrote:Who do I believe when it comes to mix ratio?

Me! 40:1 with any semi or full synthetic. No other ratio will work. I have tons of theory and science to back this up...I just can't find my links right now.

I've always run 40:1 with my 200 to 250 bikes. Why, because, well, I dunno the oils I've run all recommend somewhere in the 40 to 50 range. The big thing is to make sure and jet for what oil ratio your running. With any of the good semi of full synthetics they all seem to work well up to 50:1.

Jeb wrote:Your Kawi manual states 36:1 ratio? Wonder why the change from older manuals (mine states 32:1) . . .

my '06 manual states 32:1...

32:1 or grenading piston awaits! :)

Re: '..and I gotta put some of that toluene sitting on the shelf in my mix as well.'

Yes. You do.

Re: Who to believe?

QC wrote:Me! 40:1 with any semi or full synthetic. No other ratio will work. I have tons of theory and science to back this up...I just can't find my links right now.

I've got the same batch of theory, science and links!!!

LOL...3rd that.

Yeah, Ski this has been dyno proven(RE:more oil), but mainly with castor and smaller bore single ring engines. 20:1 castor might net 1-2 more PEAK HP than 40:1 synthetic....Not very much.....and YES to all of the above that a good jet set is implied during any of these oil conversations...

Yep lots of opinions and a few dated dyno runs and write-up are awaiting the reading for anyone who needs to know the perfect ratio tp run LOL.

Smaller high rpm engines generally need higher ratios. Guess that is why the ABS 2T engines in the RC trucks/cars run about 6:1 ratio (16% oil) but they run about 25000 rpm. Many people run the low rpm trial bikes run about 80:1. Chainsaws about 50:1 (believe my Husqvarna chain saw is suppost to run 13200 rpm). Eric Gorr has general recommendations based upon motorcycle engine size. Fuzzy will give you recommendations for carts which I believe run about generally 20:1 at what? 18000-20000 rpm?

I'm satisfied that the KDX gets plenty of lube at a 40:1 ratio even if you tend to scream the engine.

I think the best advice was to see what performs the best. Obviously the new synths are going to provide the protection you need, but the ratio affecting motor performance is usually overlooked. So now, I will be testing this on my new bike, I'm gonna start at 32:1 and jet it accordingly. After becoming accustomed to the bike's felt power, I'll try it at 50:1 and correct jetting. If there's a difference I should be able to feel it. Otherwise, why bother? If the oil is doing it's job at 50:1 then why pay more for a 32:1 ratio?