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Discussion Starter · #1 · (Edited)
Hello Everyone!

I'm having issues with cold starting after recent carb cleaning and rebuilding that I hope I can get some help with...

Here's the events leading up to this issue. I have a 2007 KLR with 11,660 miles that I haven't ridden in several, or more, months. I've been riding my other two bikes recently at the expense of my KLR. I didn't intend to stop riding it altogether it just kinda got put on the backburner so I didn't prepare it for storage and now I'm paying the price...

When I took it out of the shed a couple of weeks ago, I found that the fuel petcock diaphragm had failed and leaked fuel all down the side of the stator case, ruining the paint on the case. I generally try to avoid ethanol gas altogether but I must have put some in the tank at some point and left the fuel tank was about 1/2 full. When I looked in the tank, I found, as you probably have guessed by now, that it was full of rust.

I ordered the Carb Rebuild Kit, Extended Pilot Needle, Coaster Enricher Diaphragm Kit, and Petcock rebuild kit from Eagle Mike's to rebuild the carb and petcock after a through cleaning. I used 4.5 gallons of the Evapo-Rust branded rust remover as well as water, denatured alcohol, gasoline, diesel, followed by more gasoline to get the tank back in working order (I will say the tank came out really great: highly recommend the Evapo-rust product!). I was sure to ensure the float height was set at 17.5mm when reassembling the carb. I didn't see any rust in the carb but all the float needle and coaster diaphragm were all badly damaged/deformed. I also replaced the fuel line. I initially set the pilot needle to 1 3/8" out from the seated position. I also cleaned and reoiled the stock air filter.

After reinstalling everything bike on the bike, I found that it was nearly impossible to start when cold. Previous to this fiasco, cold starting always required full use of the "choke"/enricher for the first few seconds of starting and running. Now, I find it won't start with or without the use of the choke. I rechecked the float height using the clear tube method and that method shows the level to be correct as well.

The only method, I've been able to consistently start the bike with is to 1.) set choke to off (not enriched), 2.) apply full throttle briefly while cranking over, 3.) releasing the throttle and starter, then 4.) cranking a second cycle without throttle application. It starts right away and then idles well at 1200 rpm. After running, even briefly, it then starts and runs well. I found this method through desperation and experimentation, I never had used the throttle at all for starting prior to this issue.

I took it on a test ride and the engine runs, accelerates, decelerates very well: better than it ever has. No issues whatsoever.

I am the second owner of this bike. I have owned the bike for about 7 years now. I have never checked the valve clearances or compression before and I'm unsure if the the PO had or not. However, I was not having any starting issues prior to the recent carb work.

The fuel/air system is all stock and has not been modded with the exception of the Stead Engineering Cable-less choke.

I have also ordered the manual fuel petcock: I'm done with the vacuum-operated one!

Any recommendations on what might be causing the issue or what steps to take would be greatly appreciated.

Thanks!
 

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I don't have Gen I carburetor experience, but assume it's the same as my Gen II.

If so, this is what I would do at this point. Adjust the the idle/pilot/low speed jet needle (2) turns out from lightly seated. Then try to start the bike with say a 1/4 of the enrichner activated and with the throttle against the stop; do NOT twist the throttle as you crank over the engine.

Try the above and let us know the outcome.

Jason
 

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Discussion Starter · #3 ·
Jason,

I turned the pilot jet needle out 2 turns from lightly seated, pulled the enricher knob out about 1/4 of its travel and then cranked it over without the application any throttle. The result was the same: it continues to turn over without any sign of starting. I repeated this procedure twice more with 5 to 10 second pauses between start attempts with the same results.

Eric
 

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Your carb is probably not clean.

There are some very small drillings just in front of and just under the throttle plate. There are four of them. If these drillings are not clear then you have no functional idle circuit. If one or more of them are clear but the others blocked, you have a half-assed idle circuit. Either that our your idle jet is plugged.

What you need to do is take something pretty volatile, like a spray carb cleaner, and remove the idle jet, then spray this stuff into the idle circuit. You must be able to see fluid coming out of each of these drillings. I don't like to poke at these things because if you bust something off in them you are well and truly screwed, but sometimes you have to. If you find you have to, then I recommend a strong probe that won't weaken and break off in the hole, and what fits that requirement pretty well is to snip a few inches off of your neighbor's Fender Telecaster first string. A Telecaster will work, too, but they are pretty cliche. A Les Paul is nice but I wouldn't touch one lest you draw back a bloody stump.

Seriously, if you can find a bit of .010" electric guitar string it will work well. I think you can buy a whole set of strings for a couple of bucks. Don't know if you can just by the one wee string. If you have a pricker for a SVEA 123 or an early MSR stove, that would work, too.

Once you are satisfied that the idle circuit is clear, turn your attention to the pilot jet. I like to take the used one and throw it away and put a new one in. The reason is that the pilot jet is very small at less than .015" diameter (and that's for a #42 which is larger than stock) and they can be hard to clear of ethanol spooge. Clean it if you have no other option, using the guitar string and the carb spray. Make sure you can get the guitar string through. Clean the emulsifier holes that are cross-drilled in the jet as well.

That oughta fix you up.

You should check your valves at some point in the not-too-distant future, too, but I doubt that is your issue at this point.
 

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For the sake of the remote possibility that we could get an argument started, here is what I believe is happening with your semi-successful starting ritual. By twisting the throttle, you are opening the butterfly valve. This allows air through the venturi and across the jet needle. The needle is buried in the jet needle and the main jet, but there is still a bit of clearance in the main jet. A bit of fuel gets sucked up and dumped downstream of the venturi.

When you close the throttle and hit the starter again, there is a much larger vacuum, which picks up the fuel and gets the beast going. Once going it can keep going on the main jet.

I reserve the right to be wrong, but that's mu story and I'm sticking to it.
 
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For the sake of the remote possibility that we could get an argument started, here is what I believe is happening with your semi-successful starting ritual. By twisting the throttle, you are opening the butterfly valve. This allows air through the venturi and across the jet needle. The needle is buried in the jet needle and the main jet, but there is still a bit of clearance in the main jet. A bit of fuel gets sucked up and dumped downstream of the venturi.

When you close the throttle and hit the starter again, there is a much larger vacuum, which picks up the fuel and gets the beast going. Once going it can keep going on the main jet.

I reserve the right to be wrong, but that's mu story and I'm sticking to it.
Yeah, that's the only thing that makes half-ass sense about that particular starting method.

Jason
 

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Discussion Starter · #7 · (Edited)
Tom,

Thanks! That sounds like a reasonable explanation to me. I'll take it back off and have another go. As far as the pilot jet itself, I did install a new one when I had it open. But I will pay closer attention to the to the ports and circuits this time around. I thought I did a thorough job but this was my first attempt cleaning a carb with the exception of small lawnmower/weedeater single-stroke engines. I did go through a whole bottle of carb cleaner but I didn't make any attempt poke a wire into any of the ports. My brothers are both guitar players: I'll check to see what they have laying around! I'll be sure to report back...

Eric
 

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Tom,

Thanks! That sounds like a reasonable explanation to me. I'll take it back off and have another go. As far as the pilot jet itself, I did install a new one when I had it open. But I will pay closer attention to the to the ports and circuits this time around. I thought I did a thorough job but this was my first attempt cleaning a carb with the exception of small lawnmower/weedeater single-stroke engines. I did go through a whole bottle of carb cleaner but I didn't make any attempt poke a wire into any of the ports. I'll be sure to report back...

Eric
The engine would not "idle well at 1,200 RPM" if those idle/pilot passages are plugged. But it can't hurt to double check their cleanliness.

Jason

I'm referring to your quote in the original post: It starts right away and then idles well at 1200 rpm.
 

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If the low speed mixture screw outlet & 1st transition hole under the throttle plate are Open, it can idle just fine.

I'll suggest that possibly the non-removable cold start enrichener jet needs the guitar string pushed thru it & blasted with carb cleaner & compressed air. Pulling the handle opens the air port, but varnish must be blocking the cold start fuel jet. So technically it is leaning the mixture, rather than enrichening the cold start mixture.
 

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Discussion Starter · #10 · (Edited)
All,

It does seem to idle well wherever I set the idle speed at.

I do have the carb off the bike and disassembled again now. I will see what I can do with the ports on the enricher circuit. Not quite sure how to get at it...

Everything I've looked at so far looks clean to me. I've passed a .025 and .06 wire thru the passages on the carb body without any issue. It all looks clear to me. Looks like maybe the bowl seat of the float valve could use a little more attention. Any suggestions on how to best clean that?

I also noted that the main jet that Eagle Mike supplied is a 150. The stock size I removed was a 148. Also, the EM supplied pilot jet is a 38. The OEM one I removed was a 40.


Any other suggestions while I'm I've got it torn down would be welcome as well.

Thanks again, Eric
 

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Have you shot stuff through the low-speed air-jet and are the emulsion tubes all clear?

Do what Paul suggests with the enrichener jet.

I presume that the bowl vent line is free and clear, the diaphragm is properly installed and has no holes or tears, the vacuum ports are either connected or capped, the exhaust header is tight, the intake manifold bootie-thing is screwed-down tight and the clamps at both ends of the carb are properly situated and tightened.

If the inlet valve were not sealing against the seat the carburetor would be flooding. That said, if you want to clean that seat you can do so with a cotton swab and a bit of metal polish.

What's this about a 150 main jet? Why did he give you a new main jet and is it a Keihin 150?

Maybe you should take a look at your valve lash. Everything points to 'your bike should start just fine'.
 
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Hi,

I had this issue.
From the original post sounds like the only thing not working is the choke/enricher.

I had air leak here preventing rich mixture for start up-the plastic fitting is easily damaged.

hope you get sorted
 

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Suggested desperate lunge:

Re-install previous jets.

Even, . . . old enricher probe, if changed.

Was needle changed; slide drilled? If so, might put old needle back in; slide hole should not affect starting (IMHO).

Hey, I SAID it was desperate!

:)
 

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All,

It does seem to idle well wherever I set the idle speed at.

I do have the carb off the bike and disassembled again now. I will see what I can do with the ports on the enricher circuit. Not quite sure how to get at it...

Everything I've looked at so far looks clean to me. I've passed a .025 and .06 wire thru the passages on the carb body without any issue. It all looks clear to me. Looks like maybe the bowl seat of the float valve could use a little more attention. Any suggestions on how to best clean that?

I also noted that the main jet that Eagle Mike supplied is a 150. The stock size I removed was a 148. Also, the EM supplied pilot jet is a 38. The OEM one I removed was a 40.


Any other suggestions while I'm I've got it torn down would be welcome as well.

Thanks again, Eric
While it isn't likely your problem, those jet sizes are weird. EM's KLX kit comes with a 140, 142 and 145. It doesn't come with a pilot jet and most use the stock 40 or a 42....I'm confused as to why he would have sent you those jet sizes?

you can't compare the stock main jetting using different needles as the KLX needle itself runs richer - in any case, I'd guess your pilot is way too small (you'd need more than 2 turns!) and your main is too big (rich). Make sure you've pulled your airbox snorkle too.


Dave
 

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The non-removable cold start jet is the brass orifice next to the main jet & pilot jet tower. Its passage feeds fuel up to the brass plunger connected to the cold start cable.


@pdwestman

Credit goes to Tom Schmitz for adding this pic and labels.
 

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Check the posts in the Gen II section regarding carb problems on a 2009.
 

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Discussion Starter · #17 · (Edited)
Hey everyone,

Here's an update on my progress...

Tom, I was able to actually pick a 1st string from my brother's Stratocaster! I used it to verify the four idle circuit and enricher circuits were open. Last night, I submerged all the metal parts in Pinesol and a mix of very hot water and let that soak overnight. I bought a gallon of Berryman Chem-Dip Carburetor Parts Cleaner this morning and soaked everything in that today. I Afterwards, blew out all the passages, paying special attention to the idle and enricher circuits. Thanks PDWestmanon for the detailed labeled diagram of all the passages. That was very helpful identifying everything I needed to know!

All the passages and emulsion tubes are clear, the vacuum ports are connected. I used some Brasso and Q-tips to polish the seat of the float valve because it looked a little rough and I missed it the first time. I also used those to remove the build-up and polish out the slide: Don't know how much good that will do but it sure came out looking real nice!

The exhaust header is tight, the intake manifold is secure, and the carb clamps will reinstalled and tightened correctly. Tom, I'm not sure what you're talking about by bowl vent line. Is that what I've been calling the overflow vents (the two openings in the top of the bowl? If so, those are clear. The bowl gasket is new and in good condition.

I don't know why Eagle Mike sent me the 150 main jet and 38 pilot jet in my carb rebuild kit. I thought the listing on his website said it was for the stock set-up. I didn't look at the sizes when the parts arrived: Hell, I can't even see the small type anymore anyway! I had just assumed it was the correct size. Tom, I don't see the Keihin "K" on them Jets. I'm not certain what make they are. They only have the size stamped on them in three places around head. Maybe he sent me the wrong size with the kit by mistake or maybe I ordered the wrong kit... I don't know. I just ordered directly off the website: I didn't talk to him personally on the phone. I'll reach out to him and see what the story is.

Anyway, since I've cleaned up all the original parts (148 Main & 40 Pilot Jets) and they look real good to me, I plan to reinstall the old parts to eliminate improperly-sized jets as a cause for the irregular starting. I'll just hang on to the new parts from the kit until I can find someone who can use them, I guess.

I feel like I've done everything I know to do. I plan to reassemble the carb and reinstall it on the bike tomorrow to see how it behaves. Please let me know if you think of something else or if you think I should try something different. I surely appreciate everyone's helpful suggestions so far! Thanks for your time and effort: I'll let you know how it turns out this time around...

Thanks, Eric
 

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Tom, I'm not sure what you're talking about by bowl vent line.
The vent line is the clear-pinkish tube that attaches to a nipple on the upper left side of the carburetor; at least it is on a Gen II.

If the engine ran for more than a few minutes you don't have a vent problem. Similarly if the engine would idle properly you don't have a "guitar string port" problem.

I think Paul is on the right track with his suggestion: I'll suggest that possibly the non-removable cold start enrichener jet needs the guitar string pushed thru it & blasted with carb cleaner & compressed air. Pulling the handle opens the air port, but varnish must be blocking the cold start fuel jet. So technically it is leaning the mixture, rather than enrichening the cold start mixture.

At this point I would focus on to the cold-start enricher jet, making sure it is clear, and pay careful attention when reassembling and installing the carburetor.

Good luck!

Jason
 

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Discussion Starter · #19 ·
Jason,

I guess the Gen 1 carb doesn't have that feature. I don't see anything that looks like that at all. I went back and worked on the enricher circuit one more time. I feel confident it's clear. I'm gonna go ahead and put it back together. Thanks for the encouragement!

Eric
 

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I don't know why Eagle Mike sent me the 150 main jet and 38 pilot jet in my carb rebuild kit. I thought the listing on his website said it was for the stock set-up. I didn't look at the sizes when the parts arrived: Hell, I can't even see the small type anymore anyway! I had just assumed it was the correct size. Tom, I don't see the Keihin "K" on them Jets. I'm not certain what make they are. They only have the size stamped on them in three places around head. Maybe he sent me the wrong size with the kit by mistake or maybe I ordered the wrong kit... I don't know. I just ordered directly off the website: I didn't talk to him personally on the phone. I'll reach out to him and see what the story is.

Anyway, since I've cleaned up all the original parts (148 Main & 40 Pilot Jets) and they look real good to me, I plan to reinstall the old parts to eliminate improperly-sized jets as a cause for the irregular starting. I'll just hang on to the new parts from the kit until I can find someone who can use them, I guess.

OK, I think I got it; I was assuming you got a KLX jet kit from Eaglemike but it sounds like you got a stock rebuild kit instead? .....that means you are still using the stock needle? If so, the jet sizes make more sense though it wouldn't hurt to put the original jets in as there isn't a ton of difference. As I said in my last post, the KLX needle itself is a richer taper so it needs a leaner jet.....the needle and jet work together and you can't compare jet sizes directly using two different needles. Gen1's use a 148 main and Gen2's use a 150 IIRC.....with the stock needle, of course.

Cheers and good luck

Dave
 
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