I was just curious as to the most common or recommended premix ratio's for 2 strokes. I have heard lots of opinions.

I have a Banshee and TRX250R, both ported, piped, and jetted appropriately. I have always used maxima 927 and Super M. I have always run 40:1. Easy to mix a pint to five gallons, etc and have never had a wear problem or seizure.

However, the debate of the right ratio came up in camp over presidents weekend. I got a little paranoid by some "expert" opinions and started mixing 32:1. Not only do I have to get the measuring cup out now I also can't help but think I'm throwing my money away.

Is there a conscensus?

Thanks,

'Bob

40:1 Is just fine if you never had any problems why change





[size=24][/size]IF IT AINT BROKE DON'T FIX IT !

I always ran 32:1 Motul synthetic in my Banshee. No problems; never fouled a plug, never killed a top end.

There is no one "right" mix. There are as many opinions on this as there are 2-stroke riders.
I (way back when) used to run Maxima at 32:1.
New engine, went with Golden Spectro at 50:1 as that's what the rest of my group was using.
Now, since my brother is a distributor, I run Amsoil 2000 at a "true" 50:1.
With any mix, you have to pay attention to jetting and jet accordingly.
So, whatever you've been using, if you're happy with it, continue to use it.

97 banshee, toomey's, twist throttle, jetted and the rest is stock. I've ran Yamalube 2R at 40:1 since I bought it and am still on the original top end. If you have black oily fluid running out of your silencers, your running too much oil. I think yu'll be fine at 40:1 on a mildly built banshee. I know people that run 50:1 on em and have no problems.

40:1 golden spectro on my R. but don't listen to me, I tend to blow it up quite a bit.

Andy

I RUN THE KLOTZ SUPER-R OIL AT 55:1 RATIO AND NO PRBLEMS :dis:

I have a 250r,19CC dome,P.T.Pipe,K&N,Jetted,etc...I run mine at 32/1 The difference between 20/1 & 32/1...32/1 has 37% more fuel.This is Dirtwheels figure,by the way.The fuel that enters the cylinder cools the piston,not the coolant!!! Lean bikes seize easily,specially 2 strokes.Theoretically,more fuel equals better cooling.I have heard of 2 strokes running at 100/1.I prefer 32/1,I use Maxima 927 & straight V.P. I normally rely on info from professional sources,such as Duncan racing.Sean

It is all about your jetting. Since you ran 40:1 before, it will probably run rich now with a 32:1 ratio. The best thing to do is a plug test. I run my bike at 40:1, but it is jetted for 40:1, if I ran 32:1 it would be way rich. I use maxima castor 927.

OK, WHAT NO ONE INCLUDING MYSELF HAS NOT TOLD YOU .IS THAT THE OIL THAT YOU ARE MIXING WITH YOUR FUEL IS THE ONLY THING THAT LUBRICATES ALL YOUR BEARINGS. I.E. WRIST, PIN BEARING CRANK, BEARINGS AND ROD BEARINGS. THE MORE OIL IN YOUR FUEL THE MORE LUBRICATION. BUT THERE IS A DOWN SIDE TO THIS ALSO. YOUR PLUGS WORK HARDER TO BURN ALL THAT OIL IT BOGGS DOWN SOME WHAT. THIS IS WHY PEOPLE TRY TO RUN LESS OIL IN THE MIX. A LEAN CONDITION TO ACHIVE MAXIMUM PERFOMANCE. HOPE THIS HELPS YOU. :dis: :dis: :dis: :dis:

I run 50:1 Power Plus..99 Banshee with a 420 Stroker..

RoostKing

Scott that's good info. So that would carry over to reliability. If you're using 50:1 then your bearing and seals might not be getting proper lubracation and thus more wear. At 32:1 your bearings and seals get more lub and that would give you better reliability. Just my .02

I run Golden Spectro at 32:1 and have never had a bearing go out but the seal are starting to leak after 17yrs...

need to fix that tom, dont want to be messing up the trailer now

HEY TOM, YES AT 32:1 YOU LUB EVERYTHING MORE EFFICENTLY.

32:1, 927 and never a problem.

89 banshee, piped, jetted, ported, v-force reeds, and a hell of a lot of hard riding. 32/1 maxima 927 and never had a problem with the engine.

50:1 HERE, ON A BLASTER. PERSONALLY, MY GIRL LIKES IT NICE AND WET, BUT I'D RATHER STICK TO MY FOUR-STROKE. :wink:

doesnt matter what everyone else says as long as you run it and it doesnt hurt your bike. everyone likes it alittle different so you may never get an exact answer.

I've been running 50/1 golden spectro (as has the rest of my family since it first came out in the 70's). I am jetted for that ratio. The less oil the better the performance as long a you run the plug checks and keep the jetting right. Spectro recommends anywhere from 40/1 to 60/1. Heat ruins engines and inproper jetting causes the heat. Too rich of a setting will reduce performance and generate a lot of spooge (black crap). Most of the new generation oils all work good.

So, If I'm running 40:1 and I've ALWAYS had oil comming out of my silencer and it's running rich...

Should I change the Jet or change to 50:1 ???

Vor

switch to 50:1 then jet from there Brian. I need to do the same with an old air cooled bike that has oil coming out the pipe. I've tried leaning it out but it just keeps coming. Gonna try 50:1 next and re-jet for that mixture.

Well, my friend is also a distributor of amsoil so thats what I use. I mix 1 8oz bottle to 5 gal which is like 80/1 and have never had any problems. he has an 86 fourtrax that has the stock top end.

Ok, lets talk ratios vs. jetting. I personally run BelRey H1-R at 50:1. Ran MC-1 at 50:1 for YEARS. Remember, the more oil in your mix, the harder to burn. SO, you jet LEANER to compensate for the gas/fuel ration. Example, I have a 38mm Mikuni jetted with a 360 (i'm pretty sure) main jet, if I were to go to 32:1, I would have more oil in the fuel and the fuel would actually be thicker and not go through the jet as fast. Because of that I might run a 370 jet, BUT, you are still running the bike lean enough to burn good. There isn't that much more oil getting down into the crank to matter. I think it's all just a preferrance and all the new synthetic oils are designed to run at a leaner ratio and still give VERY HIGH quality lubrication.

So, if I move from 40:1 to 50:1 that will cause a RICHER condition because the fuel will be less thick?

I think I'll go to 50:1 and see what happens.

Vor

YOU DON'T HAVE TO REJET JUST BECAUSE YOU CHANGE THE RATIO. THAT'S BULLSH!T. BRIAN JUST CHANGE THE RATIO AND RUN THE SAME JETS IT WILL BE THE SAME. AT FIVE GALLONS OF FUEL DO YOU REALLY THINK A OUNCE OR TWO OF OIL IS GOING TO MAKE THAT MUCH OF A DIFFERENCE TO WHERE YOU NEED TO REJET? PLEASE! DAMN JET HAPPY COUCH MECHANICS :mrgreen:

VOR,
If you're going to change the fuel/oil ratio, at least do a plug check.
Rejetting is a simple, 5 minute job and no big deal.

I wouldn't think that going from 40:1 to 50:1 would be that big of a deal, but I would do a plug check to be on the safe side. You should never just blindly change your jet. You change the jets when the bike isn't set right. every bike is different.

No no no... there is a part here that you guys don't know...
I bought my bike used. I have absolutely no idea what he used to run.
The air cleaner wore out and I had to replace it. I was unable to get an exact copy. I ended up with one that was too small. So, I ended up with bad jetting problems.
I decided that I needed to have a consistant intake system before I could attempt to re-jet the bike. It was VERY far out.
I built a nice intake setup and got a good - large K&N filter for it.
Now the whole intake setup is totally different, hence the jetting problems.
Now, since I am completely convinced that it is MAJOR rich I have been putting smaller and smaller jets into it. I've not even gotten close yet.
My needle is at the very lowest/leanest setting. It runs but it spews fuel between the exaust port and the pipe. It's still lean.
I haven't even bothered with checking the plug because I know what it's going to look like.
I have a lack of power in the bottom. I have to ride it "on the pipe" unless it's flat ground, and, at the top, it seems to come up short, that is, it doesn't seem to rev as high as I think it should. In the lower gears it falls flat at the top end. Some of that could be the needle setting being at max.

Anyway... that's my whole problem. Jetting out the ass! :hit:

BTW: It's a KEHIN carb on a Yamaha Tri-Z 250

Vor

Try putting the needle clip in the middle position and then jet from there. With the needle clip on the lowest position it's in the "richest" spot (letting the maximum amount of fuel through) and is probably causing the bad performance.

The needle is set at the leanest setting... with the clip at the end of the needle which causes the needle to sit further in the jet.

I am going to move it back to the center when I try my next jet. It was put at it's current setting so that it would run last trip.

Vor

VOR

Here is an interesting article that claims the black goo from your silencer may be the result of the wrong pilot jet and shows you how to tune. It seems to makes sense.

http://www.maximausa.com/technical/lubenew...gsummer2001.pdf

'Bob

I like to use Bel Ray MC-1 at 40:1...used it for years with no problems.

What an incredibly good write up.
I printed it out and am going to take it with me to G next time!
I'll fix that d@mn thing!



Thanks

Vor

Brian do you know what size carb you have in the bike? I would start the adjustment with the air screw in 1and 1/4 turns the needle in the middle setting and a 155 main jet.

1/3 cup oil per gallon.

I use Suzuki 2 stroke oil and it burns clean, and leaves the carb clean on my pre mix rides.

Best oil and ratio I've found.