What ratio are you guys running on your 250Rs? I'm running 50:1 (just to be safe), but I thinks its too much. Its smoking a lot. Brand new top end. Thanks in advance for the help.

Just for some extra help
FMF Pipe
36mm carb (just switched from a 39mm)
open air box
UNI filter
New Top End

 

well, im mixin mine 1 quart of oil to 5 gallons of gas. 2 strokes are sposed to smoke alot..... if it didnt smoke then somethin would be wrong.

 

50:1 is less oil than 40:1, if you didn't know. 50:1 is very lean on the mix,IMO. I wouldn't run any less then 40:1. When I raced my banshee it was 36:1 and at the dunes it got 32:1.

 

We used to run 50:1 with Amsoil in our 2-strokes. The Amsoil is fully synthetic, and that is what the bottle recommended. Ran it for years in many of our bikes with little wear, and no break-downs.

You should use more oil if it is not a fully synthetic. Basically, go by what the bottle recommends. Different oils are supposed to be run at different ratios. Also, GENERALLY speakig, from what I've read, the smaller the engine (I.E. a 125 compared to a 250), the more oil it needs as it revs higher than the larger motors.

So in general, they say smaller motor, more oil. [img]i/expressions/face-icon-small-smile.gif[/img]

 

i run 32:1 in mine. i use the synthetic HP2 from honda. some dont like, i do. the bike loves it.
ran 32:1 in my banshee too.

 

Here we go again... A two-stroke is not supposed to smoke a lot. If it does, something is wrong. How many factory race bikes have you seen spewing smoke? That's right, none. If a two stroke is smoking a lot, then the jetting and/or mixture is incorrect. There should be a small puff of smoke when the throttle is opened and a light haze from the silencer at WOT, not a thick stream. If you are getting a lot of smoke with a 50:1 mixture, your jetting is way off. 50:1 isn't too bad of a ratio. Of course, it depends on what your engine is desinged to do. If it is a torque motor that churns out power at low RPMs, go with a leaner fuel mix. If it's a high RPM screamer, go richer because the fuel/oil isn't in the crankcase for very long, and lean fuel mixtures may wash the crank bearings and rings, causing them to get damaged. Everyone thinks that you can make more horsepower by mixing a lean ratio. There is no power gain from mixing lean fuel ratios. Mix your fuel for what your engine is designed for, not what everyone says is best.

Another thing is that it's easy to get confused when talking about lean and rich ratios. There are two different ratios to consider when dealing with two-strokes: fuel/oil and air/fuel. A lean fuel/oil mix causes a rich air/fuel mix, and vice versa. IOW, a lean fuel/oil mix means that you have decresed the amount of oil molecules in relation to the fuel molecules. This, in turn, causes there to be more fuel molecules in relation to air molecules. Confusing, isn't it? Just sit back and think about it for a minute, and it will become clear. Wanna know a little secret? Most factory 250s are mixed in the 40:1-50:1 range, while the 125s are mixed around 32:1 because they turn a lot of RPMs, just like ***** said above (smart girl, and pretty hot, too [img]i/expressions/face-icon-small-wink.gif[/img]). Read this article from Maxima (pdf file) to help get you in the ballpark for your jetting.

 

I RUN 32: IN THE KX100

 

I made a mistake. I'm running 32:1 (sorry brain fart), I think its too rich. It didn't smoke as much before the rebuild.

 

I've been running Amsoil at 50:1 in both the Rs here for over 10 years and have never had an engine problem due to the fuel/oil mix. I do agree; non-synthetics should be mixed differently.

 

Amsoil 100/1 no problems here. I haven't seized or blown a piston since the first year I bought my 86 250r in 1990 when I ran yamalube.