Maintenance & Technical > KX250 / KX125
Getting the jet needle out of the throttle valve?
mustangfury:
yeah i tried it a couple of times and did not see any difference. I don't think it is the issue but with the amount of smoke that comes out all the time, it still could be an option. But, no, i did not see any difference tilting the bike one way or another. I'm glad you told me about this method of checking it. I had been wondering how for quite some time.
thanks for the input on the float level too.
Friar-Tuck:
Hey Stang,
I think your making a good decision and yes like Big Bob says the float level will have an affect on your jetting also.
There should be a pretty good write up in your clymer on how to set your float height if you need it and the float height should also be in there usually measured in MM.'s
Should you find you don't need several of the jets you bought you should be able to sell them at what you paid for them if they are still in good shape.
If you set the float height when you put the carb together you shouldn't have to remove the carb again.
The mains are changed through the hole the 17mm nut bottom of the fuel bowl.
Get yourself something like a small chip dip tub or the bottom of a plastic bottle and cut it to fit under the float bowl so you can get your fingers to the drain plug and catch the fuel in the tub. It will keep from dumping the fuel on your case & chain or onto a rag.
Hang in there,
Tuck\o/
mustangfury:
i didn't think about changing them through the bottom of the bowl. that will make things a lot easier.
What size jet should i start with. i know it is best to work from richer to leaner to avoid engine damage but I also know i have a very rich jetted carb, so a change of -12 on the size might not be a bad thing. Is changing from a 170 main to a 158 main a huge difference?
I guess i'm just wondering what the overall strategy is. The strategy i had in mind was to go to 158 and see that the plug is a nice brown or if it is white i know to go up, then work our way up one jet at a time and go till we see oil then go back down one?
...process of elimination.
The only other way I thought of is elimination from high main to low main, reverse of the previous. This sticks to the start rich and work your way lean, but the only reason i wouldn't want to do that would be because i don't want the silencer getting filled with oil and giving me bad readings out the muffler as i go lower or having to repack the darn thing every time i try a lower number. Taking it easy like you suggested around the farm will prevent engine damage for that short period of time i ride while allowing me to start lean.
What fuel mixture should i run for this? 32:1? 40:1?
40:1 is currently in it. I would like to see it run 32:1 if it can though.
Friar-Tuck:
Stang,
Stick with one change at a time.
Start with the FMF suggestions and we'll go from there.
The only change you will need to make is put in the 158 main. The Bel Ray Oil ratio is the same, pilot air screw etc.
You can run any mix ratio you want and still have a good running bike.
Patience Grass Hoppa.. I know how hard it is to just keep the changes slow and one at a time. This will pay off in the long run.
Take your time swapping out the main through the bottom of the carb so as not to cross or strip the threads, it really isn't so bad. You will need a small (1/4" drive) 6mm socket or jet wrench.
Here is a trick motion pro: http://www.motionpro.com/motorcycle/partno/08-0023/
Craftsman socket :http://www.craftsman.com/shc/s/p_10155_12602_00934602000P
No worries yet Matey!
Yes also on the rich to lean direction. Why take a big chance on ring, Or Worse piston seize.
I don't want you to feel like I'm yelling or you're in the principals office. Consider my suggestions and weigh them against what you have read in your clymer and what the recommended jetting specs from the pipe manufacturers are.
There really is no magic #'s as the variables are always different and changing.
Weather,elevation,wear and tear on the equipment etc. Once we get you either to a point you happy with the performance, the only changes you will have to make jetting wise to stay in the ballpark is winter summer main jet. an 8 minute process at most.
The more critical you are with performance the more changes you will have to make.
As an example a Mechanic may change jetting on the bike he's responsible for through out the day as the relative humidity,temperature and track conditions change from morning 'till evening.
Tuck\o/
mustangfury:
thanks i'll let you know how things go once i get the jets in and give er a test run.
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