So my bike wouldn't start and was running poorly. Turned out to be one of the intake valves. No clearance at all, so I put in a new shim and she was starting and running great, problem solved.

Except.................for a while the idle was hunting around. One second 2500 then 1500 than 2000. Seemed to after riding and revs where up or gearing down to a stop. So vacuum leak or air leak right. Okay so the bike shop says check your pilot jet/float height/ and for air leaks, okay no problem.

So today I check for air leaks, can't find any, adjust the float height ever so slightly as it was not parallell with the carb bowl edge. What happens next is a mystery. She won't start and after finally getting her going she sounds like a chopper and blowing black smoke out the pipe. Open the air box and slight improvement, she is crazy rich. I've never seen this kind of change. Did I over due the float. I tried 4 or 5 different levels including the original and the problem stills exsists.

Through trial and error, the pilot system seemed to be ok, because after one start up it ran perfectly, little idle hunting and when I hit the throttle back to major fuel consumption/black smoke and dead. The needle isn't binding up in the carb, the needle and pilot adjustments weren't tampered with, spark good, float is stopping fuel and no overflow. So I took the whole air box and intake sytem off with just the motor and carb so I could watch the slide and air throttle plate open. The slide was vibrating up and down, not smooth at all, and the amount the slide seemed to be pulling the needle up compared to the amount the air throttle plate was open seemed to large. The slide was 1/3 up or more with the throttle air plate just slightly opened.

I checked the slide, clip, needle, diaphram and only issue was the diaphram seems very stretched. Probably original diaphram with 14500knm on it. It sits okay in the carb after you poke it in, but its elasticity is definately gone. Could the old slide be pulling up to high with the vacuum and overwhelming the throttle air plate air intake and creating a very rich mixter???? Never drilled slide breather hole to 1/8, I think.

No snorkel
No backfire screen
#40 pilot 2.25 turns out
Needle 2nd poistion down from top
full exhaust system
drilled crankcase vent hole

 

try giving it a clean Shawn.

repco or super cheap auto have carby cleaner.

dump your fuel, water can cause the fuel to ignite to late, cause black smoke.



if not, you can borrow/buy my standard carby if you want.

perfect excuse to buy a tm33

 

The old adage, "always check the last thing you did" may apply here. You got some real issues after resetting your float level. It sounds like you set the float by sight and not by fuel level. Personally I think this can be highly inefficient. Oddly many floats don't have the same exact buoyancy which can negatively affect the real fuel level. Try setting the float by the "clear tube" method to get a real fuel level. The KLX seems particularly sensitive to fuel level. Once you get that issue back under control, you at least can eliminate that problem and move on.

Your observation of the "floppy" rubber on the diaphram may be a non-issue. Not seeing yours in person, I can't be sure, but these diaphram rubbers always look floppy to me. They have to be quite flexible to operate properly.

 

did you look at the float needle? It could be worn or is sticking. just fishing here

 

I would say the float needle is fine. If it was sticking the carb would be to lean or flooding. Its definately not to lean and even though the motor is getted flooded no fuel is coming out of the carb overflow hoses.

What is the "clear tube" method for setting the fuel level in the carb? What is the float level specification?

Does the slide move smotthly or would it vibrate up and down as it moves?

There are no rips in the diaphram, and the float doesn't have any leaks.

Really at a loss here.

 

Well the verdict is in. The problem was plain carelessness. When I took out the main jet and the needle jet holder the needle jet must have fallen out and I didn't notice. After looking at a few carb diagrams I realized there where three parts to the main jet, needle holder, and jet. I only installed two parts.

It now makes perfect sense, it was runnning so rich because without the needle "jet sleeve" the fuel was unrestricted from the carb bowl and flooding the motor.
Havent installed the needle "jet" yet, but I have confidence that all will work fine.

 

There you go. Congrats on staying with it. And once again that old adage applies..."check the last thing you did"...LOL!

On the clear tube fuel level check I mentioned, you get a clear piece of tubing the diameter that fits the drain spigot on the bottom of the carb bowl...a piece of plastic battery overflow tubing works great. Set the carb on a pair of wooden blocks or in the open jaws of a vice, keeping the carb dead level. Open the drain screw on the carb bowl and fuel will flow up the tube and to the level at which it is inside the fuel bowl. This is the real and exact level of fuel in the carb bowl. If it's outside the recommended spec, you open the float bowl and adjust the float tang where it touches the needle as needed to get the level to the proper spec. No special tools are required. The shop manual specifies a factory clear tube device that attaches to the carb, but this is a pure law of physics deal, and the clear plastic tube works every bit as well.

 

Right on, congrats on the fix

 

So my room mate found my needle jet next to the BBQ outside on the driveway. I installed it and all is good again. Never happened to me before lossing a part, so in the future I need to very dilegent about small parts and keeping track of them.

Thanks to all who helped out.

 

but not those of us who are going to give you @#@ ... "don't forget to put the gas tank back on." .... "those spark plug thingies are kinda important, might want to hook those up" .... "check for pistons, if missing bike won't run right"

all in jest, we've all been there, done that. Some of us will even admit to it.

Glad your roomie found the missing parts before you tore the whole bike apart!