Won't start, help!!!

[James670X]

I have a 2004 KX125 and the bike will not start for me:?. It's strange because the bike has run for others in the past. It has spark and the carb is getting fuel, however when we pulled the carb off, it was leaking straight gas and oil (they weren't mixed ).
Any feedback will be greatly appreciated, as I need to get this bike running asap.

[r1ray]

 it was leaking straight gas and oil (they weren't mixed ).

[/quote]

That doesnt sound right. If its a 2 smoke yer gas and oil should be mixed before it goes in the tank

[Johnniespeed]

Assuming it has compression, was the spark plug wet or dry after kicking it many times ?
 What color was the spark plug tip and insulator ?  I dont think it is possible to mix gas and two stroke oil, pour it into the gas tank and then have it separate after the carb or before the carb.
  What events lead up to the no start ? was it running great and stalled ? Plug fouled ? Did you try a new plug ? ( even if the old one looks ok )

[James670X]

 It does have compression, 130lbs. worth (spec. is 180lbs. though). The old plug was in fact wet and black in colour; I have not taken a look at the new spark plug however. I dumped Bel-Ray H1R into the tank when I filled the bike last night (mixed at 32:1). Straight oil and gas dripped from the carb when I went to take it off of the bike . My Dad told me that the bike did in fact run nicely for him last weekend. I have yet to hear the bike even attempt to run .

[FuriouSly]

I dumped Bel-Ray H1R into the tank when I filled the bike last night (mixed at 32:1).

Hmmm, not the best way to mix 2-stroke fuel.  It is possible that if you dumped what you believe is the appropriate amount of premix directly into your bikes fuel tank that it did not mix, especially if you poured the premix in on the petcock side of the tank.  If the temperature of the premix is cold and thick, it takes some agitation to mix it.  Pouring fuel into the tank might not mix it correctly.  Always put the premix into a gas jug, pour in the fuel halfway, agitate it a bit, then pour in the rest of the fuel.  Works everytime.  Sounds like the mix is way too rich and that you have slimed the carb, reeds, and crankcase chamber with the premix.

Below is only an opinion of what to do.  My 2 cents.

So the bike was sitting for a week.  Was the fuel petcock on?  If so, did it leak fuel out the overflows?

Sometimes the carb float valve in the bowl will let too much fuel in and it will run past the reeds into the crankcase chamber without even running out the overflows.  This fuel will evaporate leaving behind a heavier concentration of mix (in the carb and the crankcase).

The fix is to take the plug out, take the tank off (or plug the breather in the cap), and then tip the bike upside down.  Slowly crank the bike over until you are sure piston has lined up letting the accumulation of fuel/mix in the crankcase run out the plug hole.  If the residue coming out is really thick, you can upright the bike and pour some mixed fuel in the plug hole (about 6oz) and then repeat the process.

Sly

[James670X]

Would spraying ether down the cylinder help alleviate the problem described by FuriouSly?

[James670X]

I believe I just stumbled across the problem, the bike is missing the float valve o-ring inside the carberutor (part# 92055B)

[FuriouSly]

Kinda weird to have that happen all of a sudden.  Are you saying that the conical rubber tip of the float valve is bad?

It still amazes me how much engine trouble the dang carb float valve masks.  It screws with jetting, idle, hard starts, lean conditions, etc...  A new float valve with proper adjustment for your carb is the number one troubleshooting start.

Let us know if you get it running... don't forget to set the float height, it's very easy.  Just find the measurement (usually in mm)  and mark it on a thin piece of paper (like a paper match) and then use it to measure and adjust the height.

Sly

[KXcam22]

James,
  I don't mean to confuse things but my 500 doesn't have that o-ring either, unless the diagram is actually showing the rubber tip (which I don't think even comes off).  When you follow Sly's instructions a word of caution.  Tie the plug cap out of the way of the cylinder hole since there is an incredible amount of spark, enough to make it out of the cap and ignite any stray gas when you turn it over.  Get's really supprising when the bike bursts into flames. Sounds far-fetched but I did that once.  Cam.

[FuriouSly]

That's funny Cam,  did you lose any hair during the firefight??  hehehe.

I would not suggest spraying ether down the plug hole.  It is very volatile and has no lubricant in it.  It will strip away the premix on the cylinder wall and dry start the piston rings if you are not careful to slow kick some new fuel mix into the jug before firing it over.  That's why using premixed fuel to clean out the crankcase chamber is safer...  with the added plug cap info from Cam.  I forgot another hazard.  Make sure not to let the fuel accumulate in the exhaust pipe as well,  since it can cause an explosion in the pipe and possibly split it, especially an FMF.

Sly

[KXcam22]

Sly,
  No hair loss. Luckily I always keep a fire extinguisher on the frame of all the shop doors so it was a mad dash there and back. Actually didin't even do any damage (except when I filled my shorts). Cam.

[James670X]

Update: My brother and I tipped the bike upside down as suggested, there was in fact gas in the crankcase. Also I believe I solved the problem causing this, the bike has a bent needle jet.