2-stroke mixture

[03CR250]

Is there anyway to tell how rich or lean your jetting is without examining the plug?

Also, is there anyway to tell if your premix has too little or too much oil in it?

Thanks,
Clay

[redrider ex]

then you can't go wrong

[bmf400ex]

Originally posted by redrider ex
then you can't go wrong

ditto, but u still gotta look at da plug. really u can run whatever mixture u want, within the limits of course. but you have to jet accordingly.

[Gusto]

Ok, call me crazy..you can tell if your bike is lean or rich by looking at your exhaust. If you have experience in jetting your bike, you should be able to look and "feel" which way you are going with the jetting. But the only real way to tell is by riding that bike wide open, shut it down and pull the plug. Don't putt it back to your pit and pull it...try to do it right after you have it wide open. Also remember how it felt through the gears...where did it bog or hesitate? That will tell you how to jet also. With that note, don't cut the recommended ratio with oil. Some bikes need to have that oil and some can do with less. Pistons/rings and a crank can get expensive....
If your going to have that bike for awhile and don't want to pay a mech to do your jetting, then learn how to pull that carb...should only take you about 10min once you get it down. Have fun and ride hard.

[Hoodeye3]

Red rider & Gusto have great advice definitely pick up a ratio mix cup (there not much $) because you dont want to guess here , If your mix ratio isnt consistent while trying to get your initial jetting down, it will just make it more difficult and possibly costly! CRs from the factory usualy arent that close and are a pain to jet -spot on- It just takes a little time. Also the standard ratio is 32:1 , But there are many good synthetics out now adays and some people will lean the mixture out a bit more. If shes flat, bogs or hesitates out of the hole to mid work with your needle then air screw , For your main go with Gustos advice pin her and shut her down then pull the plug (ashey white and dry- bigger main- black sooty and wet -go smaller-. Good Luck

[03CR250]

I did get a ratio cup and some nice synthetic premix oil, but I wanted to make sure I'm using it right. For instance, if I'm using the 32:1 measurement line for 2 gallons, does that mean you use 2 gallons of gas with the oil from the cup or should the combined mixture of oil + gas equal 2 gallons?

I was told that CR250's run fairly rich with the factory carb settings. Right now its bogging out of the hole, but it seems to run fine at WOT. Is that usually a sign that I need to go leaner with the jetting? Should I lean it out some with the air screw before trying to re-clip the needle? Thanks again. I've always owned 4-strokes in the past. This is my first 2-stroke bike.

-Clay

[bmf400ex]

Originally posted by 03CR250
I did get a ratio cup and some nice synthetic premix oil, but I wanted to make sure I'm using it right. For instance, if I'm using the 32:1 measurement line for 2 gallons, does that mean you use 2 gallons of gas with the oil from the cup or should the combined mixture of oil + gas equal 2 gallons?

I was told that CR250's run fairly rich with the factory carb settings. Right now its bogging out of the hole, but it seems to run fine at WOT. Is that usually a sign that I need to go leaner with the jetting? Should I lean it out some with the air screw before trying to re-clip the needle? Thanks again. I've always owned 4-strokes in the past. This is my first 2-stroke bike.

-Clay

try backing out the air/screw and the cup ratio goes like this. put in oil to the 32:1on the 2gallon mark then mix with 2 gallons of gas, that means there is 32oz. of oil per gallon of gas.

[YZROOSTINYA]

32:1 means for every 32 parts fuel there is 1 part oil


and so on

[Hoodeye3]

That would be a squech rich BMF, YZs a little closer

8oz. = 2gallons 16oz= 4 gallons and so on e for the 32:1 mix

[Gusto]

Have you done anything to this bike since you bought it, ie. pipe, filter, reeds? If it's used, did the guy race it? Has the weather gotten colder since the problem started? You need to figure in all these variables plus some other ones before you start moving the needle up or down. If the bike has an owners manual, it should have a chart in it about the jetting changes. If you have the manual and your bored sitting on the throne....read thru it. It can only make your problems easier. Those 2 strokes are fun and finicky.

[03CR250]

I bought the bike new from the dealership, so I'm assuming it has the factory carb settings. I've only had it a week, so it has no modifications yet. I opened the air screw just a hair and it seems to run a little better now. Its not bogging anymore. However, I noticed a little oil splatter from the rear of the exhaust after riding it yesterday afternoon. Is this normal for 2-strokes?

I used a 32:1 mixture with Motul 800 (synthetic) and 93 octane gas. The mixture is fresh.

By the way, this may be a dumb question, but how can you tell when a plug is fouled? Will it run like crap or will it not run at all?

Thanks as always...

[Gusto]

Little oil splatter is fine, and normal for the 2 stroke. When to plug is fouled it won't start cause it's saturated with fuel/oil-real rich. Make sure you run that thing like you stole it, if you start to putt then the plug may start to foul up. 2 stroke riders always carry a spare plug if not running around a track...:D

[MichaelS693]

i mix 4 oz.'s to a gallon on my blaster and im gettin the 240 kit would i have to change my ratio of oil to gas up due to the more cc's and would i change my mixing ratio up if i changed my jetting i am unsure and need some help guys but i dont think it should change for either just not sure and wanna be positive so i dont blow my bike up