A Real Puzzle in Carburetor - Kawasaki KLR 650 Forum
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post #1 of 7 Old 11-22-2012, 12:36 PM Thread Starter
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Join Date: Oct 2012
Location: Silver City, NM
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A Real Puzzle in Carburetor

I'm surprised and disappointed that there've been no replies to my original question. Oh well.

This morning I went out there with fresh eyes and viewpoint after stewing over it most of the night. I took several steps -

1) Removed fuel and vacuum lines from tank valve. Opened tank valve, and got nothing - as it should be. Then connected a separate piece of tubing to vacuum line at tank valve and sucked on it. Gas flowed readily.

2) Removed bottom bowl (float bowl ??) from carburetor, got down close with flashlight and with reading glasses on, moved the float up and down and could clearly see the needle rising and falling with movement of float.

3) Made sure carb was vertical, left bowl off, let float dangle, connected tubing to tank valve vacuum port and sucked on it. Gas poured readily thru the opening for the float valve.

4) While gas was pouring I moved the float up and down and when up, the gas would stop flowing. Did this several times and seemed as tho' the float rose pretty high before shutting off, but it did shut off. (I cut a sheet of soft plastic to make a funnel for the gas to run down and into a cut off gallon jug. I also kept a dry chemical fire extinguisher next to me)

5) Removed float and needle and checked needle tip for any marks or material and checked float for leakage. All looks fine and I was surprised because I expected to find the float needle stuck open or partially open.

6) Put it all back together, making sure o-rings, etc. were seated properly. I had read last night where a fella said an easy way to check float level was to connect a piece of clear tubing to the bottom drain port of float bowl and start the engine. Holding the clear tubing up beside the carb, gas would rise in the tube and you can see the level. Makes sense -I've done a similar thing with a garden hose to check for level foundations. I think he said it should be about 1/8" above where float bowl mounts on carburetor.

7) HERE'S THE KICKER - With the engine running.....THE FLOAT BOWL REMAINED EMPTY ! ! ! After waiting several minutes and watching all, still no gas in float bowl, so I took the end of the tube and gently sucked on it, then blew into it. Yup - that float bowl is most definitely empty. No gas at all in it.

8) To my little pea brain, seeing that made it obvious why I was having a problem. Give it choke and it opens the enrichment circuit and feeds gas to the engine from a different part of carb. Give it throttle and it gets air but no fuel and starves out.

9) All well and good, but how can that be ?? Gas flows readily from the needle area when needle and float is removed. Float and needle move freely when moved gently by hand. Gas pours out when float is down.

10) A thought just now occurred to me.....when I put the float bowl back on, it's conceivable that something could be catching and forcing the float up and shutting off the flow of gas.

I'm taking a pissed-off break right now and will go back out and fool with it in a bit.

Any ideas would be appreciated...............Lar.
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post #2 of 7 Old 11-22-2012, 01:27 PM
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Join Date: Oct 2006
Location: Pefferlaw,Ontario
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A stab in the dark for shits and giggles...float in the right way or upside down???
I don't remember IF it even possible, sorry suffering from a migrain ....
When you put the float valve back in with the float, you did attach it to the little arm of the float right?
Perhaps the float is caught on something in the bowl if you didn't get it lined up 100% correctly? Possibly holdng the float up and not allowing any fuel to get through.
You attached the clear hose to the botton of the float bowl....correct....did you make sure that system wasn't plugged? Did you try and blow through it? If blocked it won't allow fule to drain out of bowl. So you won't see any gas in the clear tube....?
Not sure if it goes 1/8" higher than the gasket between the bowl and the body of carb either???

The engine is creating suction correct? Or perhaps the hose is colapsed? Is the vacuum line solid and not soft?

My head hurts....will try back later...sorry.

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post #3 of 7 Old 11-22-2012, 01:46 PM
1st Gear
Join Date: Dec 2007
Posts: 39
Check the vents in the carb and the gas tank
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post #4 of 7 Old 11-22-2012, 01:50 PM
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Join Date: Apr 2010
Location: Gateway to Death Valley!
Posts: 1,928
My guess is that the vacuum line on the back of the petcock is bad somehow.
The choke circuit probably is sucking enough air to get gas out of the tank, I've never tried sucking on the gas line to see though.

Also I would double check that the carb is assembled right.

No eye has seen, no ear has heard, no mind has conceived what God has prepared for those who love him. 1 Cor 2:9
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post #5 of 7 Old 11-22-2012, 05:25 PM
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Join Date: Oct 2006
Location: Pefferlaw,Ontario
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The next mod is the "T" mod.....search it out....lol. It would stop that from happening.....many with the newer version bikes think it's still not worth doing now as the hose is routed where yours is. To each their own.

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post #6 of 7 Old 11-22-2012, 07:21 PM
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Just ME, or is there an ECHO hereabouts?
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post #7 of 7 Old 11-23-2012, 08:39 AM
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Join Date: Oct 2006
Location: Pefferlaw,Ontario
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LOL...just goes to show you how bad yesterday was....I never even realized what you posted before me in the other thread....lol.

It is something I normally don't think about much seeing I never have this issue....the "T" mod was one of the first bunch I did many years ago. But, I have seen the same thing but not enough to stop the fuel flow on a bike I was working on. Yes it was pulled out and modded just for good measure.

Maybe I can think about doing something constructive today.......augh!!!!!

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