no fuel suction - Kawasaki KLR 650 Forum
1987 to 2007 Wrenching & Mods For maintaining, repair or modifications of Generation 1 KLR's. 2007 and earlier.

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post #1 of 12 Old 11-04-2014, 01:55 AM Thread Starter
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no fuel suction

Hello everyone,
first of all greetings to all forum members. i'm new kawasaki klr rider. last month just bought a klr 650 tengai 1990 year, it had a starter problem, but after change of starter gear, the all starter mechanism works fine. Now o have a problem with fuel suction to the engine. As i hit the starter, the engine just turns over and over. After that checked spark plug, it's dry, so no fuel to engine through carb. The ignition is ok, spark plug ok too, when i fill gas directly to cylinder the motor starts for a little time and then stops. Cleaned the carb twice, but no luck. The diaphragms on carb is ok, cleaned the main and the pilot jets, everything, every hole. The petcock works fine, i can fill the carb bowl by manual suction. Where could be the problem?

P.S. Sorry for my bad english

Last edited by zulas; 11-04-2014 at 01:58 AM.
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post #2 of 12 Old 11-04-2014, 09:26 AM
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Location: Woodridge, IL
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I assume when you 'fill the carb bowl by manual suction' you are saying you are applying a vacuum to the petcock vacuum hose. That suggests the petcock, fuel tube, filter (if any) etc, are all good.

Are you using choke to try to start the bike? I know you mentioned you've cleaned all the jets but I wonder if you need to take another look at the pilot jet.

If the carb is dry and you try to start the bike a couple times, is there gas in the carb bowl? That tells us if the carb is providing suction to the petcock.

Assuming that's good, have you inspected the carb boots? Perhaps you have a nasty split in the boot between the engine and carb? Is the air filter clean? Is air passing through the airbox properly?
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post #3 of 12 Old 11-04-2014, 10:06 AM Thread Starter
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yeah you are right, i filled the carb bowl with manual suction from vacuum hose of the fuel tank petcock. During the cleaning i found the main and the pilot jets were full of dirty, so i cleaned, i couldn't put a wire through a pilot jet, but now everything seems to be ok. Also what does the starter jet do? do i need to clean it, because then i put a wire , somewhere it stuck's.
Yeah i'm using a choke while i start the engine. The air filter seems to be fine too. I think i'm going to check the vacuum leak with an aerosol spraying around the carb.
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post #4 of 12 Old 11-04-2014, 11:16 AM
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There are two removable jets, the pilot jet and the main jet. The pilot jet is the main fuel outlet up to something like 1/4 throttle. When starting and idling, this is the jet you are primarily using. The choke is another fuel source when you use it.

If you aren't getting gas in the cylinder but have good suction from the carb, I would look at the pilot jet again. It's the smaller brass jet.

Try not to push a wire through them unless it's a single strand of something very small, and use copper wire to help prevent damage. You don't want to accidentally make your jet larger. I find that I can use the little red tube with my carb cleaner and blast cleaner through the jet. If it doesn't squirt pretty far, then the jet is still blocked. Sometimes blowing air through them 'backwards' can unblock a piece of shmutz.

You are not likely to have a lot of success looking for a vacuum leak when the bike isn't running. The kind of damage you'd need to have on the boot to keep it from starting would be a huge gash.

And since it's a KLR, it'd probably start then, too.
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post #5 of 12 Old 11-05-2014, 11:33 AM
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Join Date: Oct 2013
Location: Chilliwack, BC, Canada
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Is the carburetor float bowl filling to about the gasket line?

You can place a piece of clear plastic tubing such as PVC onto the bowl drain, hole the hose looped upward and open the bowl drain screw. With vacuum applied to the fuel petcock, the fuel level in the plastic tube should rise to about the level of the bowl gasket.

If the bowl is filling to this level, then engine should start and run and/or continue to run if fuel is introduced into the intake. If conditions are quite cool, the engine may not continue to run without choke but usually they will run for a least a short time.

If it will not run with the above fuel level, the carb. requires cleaning. There is not much which substitutes for high pressure shop air for clearing passages.

Check the pilot jet as kyzon recommended, as the holes are very tiny. Unless you have tiny jet drills, an ultrasonic cleaner may be the alternative. One can usually see whether the pilot holes are open although build-up can reduce the hole size while still showing light.

If it does not show bowl gasket level, try checking fuel delivery by running fuel into a container from the bowl drain (with suction to the petcock) which should flow at least a couple of cups volume in a minute.

Troubleshooting strategy from here requires determining whether there is adequate fuel flow into the carb. or not. If adequate fuel flow, look to the carb. If not, look to the petcock, tank screens, fuel hose. carb inlet/needle & seat.
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post #6 of 12 Old 11-05-2014, 01:24 PM
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It seems to me that if the carburetor works well enough for the engine to start, it should work well enough for it to continue to idle. This makes me wonder if once started it is getting too much gas through a leaking float valve at the entrance to the carburetor or too little gas due to low suction at the petcock vacuum connection.

I would try starting and running with the manual suction applied to the petcock and the stock vacuum line back to the carburetor plugged. If that did not work, I would check the level in the float bowl and the flow rate as Normk suggests above.
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post #7 of 12 Old 11-07-2014, 02:24 AM Thread Starter
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Thank you all for help and replies.
Finally managed to start the engine! now everything seems to work fine. Just putted the carb in the acetone for 24hours, and after all cleaned all holes with compressed air, now moto jumps well, only need to setup the idle RPM, and the temperature gauge seems not to work. Also is it possible to tell is the doohickey need a new setup or replacement? And maybe someone knows what is the diameter of oil seal in the rear shock? the shock is leaking oil, and i will try to rebuild it
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post #8 of 12 Old 11-07-2014, 11:46 AM
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A mirror will allow you to see whether you managed to disconnect or fail to reconnect the temperature sender which is beside the spark plug. I've become quite good at reconnecting these with tank in place for reasons which will be obvious. (Insert head banging icon here) Gen2 are much more difficult than Gen1 because the air injection piping takes up some of the hand space.

Glad to hear that you have the carb solved. Acetone is quite effective for removing many types of deposits so a good call on your part. Next time acetone isn't as good as something else so I've found one sometimes needs to try more than one solvent.

Nothing better than high pressure air, so long as one takes things apart so that something isn't damaged. I've seen many traumas over the years where someone tried to clear a carb without removing the float bowl, diaphragm, or other closed space.

Doohickey is a tough one as haven't found a way to see it through the plastic screw plugs in the engine case. I've had to pull the stator (outer) cover to gain enough space to see. FWIW, it requires some attention to detail even with the cover off so make certain that you know for what to look. I look, first, for the torsion spring used by the preferable EM solution.

Gen2 are more difficult because they use an original one-piece Doohickey so first here's what I do for Gen1:

If there's a coil spring in place, I look for the weld which joins the two pieces forming the original Doohickey. Regardless, poke the coil spring (even if has the one piece machined replacement Doohickey to make certain that there is tension on the spring. If the spring isn't under tension, it needs replacement with the shorter EM spring, even if has an EM Doohickey. If the spring is broken, you almost certainly have the stock Doo.

FWIW, if the spring is broken and you wish to continue riding, you can use a long screwdriver to provide spring action to adjust the Doohickey in order to adjust. Then, don't delay, order the kit and install when can. I don't anticipate any problem riding in the short term with a broken spring because of seeing so many broken ones which soldiered on. The broken end piece will almost certainly be in the oil pump pick up screen. I like to clean the pick up screen at this point regardless although discount the level of panic often reported at the amount of silicone "worms" often found in the screen. They don't cause any problems which simply points to how far off is our intuition in these cases.

Gen2 are at once easier and more difficult. If the spring is a coil and has no tension, it is almost certainly an original. One really has to have clean glasses to see the difference in the original (one piece) Doo lever and the one piece EM unit. If it's a one owner 2014 not much question.

Also, FWIW, I'm about 100% on saving the outer housing (stator) gasket and reuse with silicone or flange sealer. As for the inner gasket, I haven't pulled the inner housing for several years as manage to spread the end of the spring to unhook from the peg in the cover without separating the inner cover. Likely done a dozen+ without removing the inner cover.

Hope some of this is helpful.

Shock seals are advertised on EBay and other places by application. I don't see the dimensions in my notes so hope someone has them.
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post #9 of 12 Old 12-07-2014, 04:27 PM Thread Starter
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Thanks for reply,

Now the rear shock is fully rebuilded, and the engine runs at normal idling speed just fine, checked the valve clearance, and the compression, everything is in normal range. Found that the auto decompression spring is a bit stretched so think i will replace it ( if i will found for a normal price for shipping). For the temp gauge, i found that there is no sensor near spark plug, just a 6 head bolt, the previous owner removed the sensor. Where could i find this sensor for a reasonable price? maybe there are any other suitable sensor ( from other cars or something else)?
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post #10 of 12 Old 12-07-2014, 05:22 PM
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Posts: 1,481
Does that bike have a temperature gauge or a warning light?
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