2009 KLX 250 trouble starting | GTAMotorcycle.com

2009 KLX 250 trouble starting

numitor

Member
Hi guys,

I'm a total noob with motorcycles but I tried to search the web a bit before posting here. The bike has an FMF q4 with dynojet.

I am pulling the choke fully when starting cold and the bike starts up right away. After I wait a bit and push the choke and the idle is normal I turn off the bike. Now when it's warm it has trouble starting again, it won't start at all if I don't pull the choke again. And sometimes even if I pull the choke.

I checked the battery and it's returning 12.5is V, spark plug looks ok too.

What can I do to further diagnose this ?

Thanks in advance,
 
I did go for a ride and after I refueled the bike won't start. Now before I get stuck somewhere I wanted to reproduce the problem in my garage.

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I did go for a ride and after I refueled the bike won't start. Now before I get stuck somewhere I wanted to reproduce the problem in my garage.

Sent from my Nexus 5 using Tapatalk

How long a ride was it?
 
It was a short ride, I just wanted to take it around the block to test how it runs, less than 10km

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I did a quick google search and it seems that this problem is common for this bike:

http://www.kawasakiforums.com/forum/klx-250s-71/new-klx250sf-hard-starting-36633/

This is a well documented problem and it’s inexcusable that Kawasaki let these bikes out of the factory with such a fundamental design flaw (regardless of whether EPA regulations restricted the jetting or not). I like to trouble-shoot & tinker as much as any biker but only to the end of riding, and a brand new bike should not require tinkering to get it started.

A few suggestions to help with this problem are posted in that thread... good luck, and let us know what worked for you!

This suggestion amused me:

Another trick, also explained elsewhere in this forum is to lay the bike on its left side for several seconds with the petcock open, then lift it back up and it should start.
 
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Sounds like they are too lean from the factory. Did you rejet when the pipe was added? If not, you're likely starving for fuel.


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Thanks a lot of your suggestions!

Based on what I've been reading it sounds like it's running lean. In forum post posted by Xhumeka, some users seem to suggest drilling the starter jet. The previous owner didn't do the pipe install but he gave me the old pipe along with a Dynojet box with a couple parts in it. He told me it was re-jetted. But the start symptoms along with popping backfire when decelerating point right at the carb jetting.

I think I will take out the carb, clean it and check the jets. I will be following guides I find online but If you guys know any good resources for carb removal / re-jetting please share!




 
I drilled the starter jet with the 0.018”. It helped with cold starts (not sure about the warm start problem), but it's not perfect. I read somewhere that a 0.02" might be better. Where ever you buy the 0.018", you might consider picking up the 0.02 as well, just in case. And in case it wasn't written, you hand turn this bit with a special holder.

As a side note... draining the carb actually helps a lot at the end of the ride (either running with the petcock in the off position, or through the drain valve)
 
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An iridium plug in mine helped a bit with the cold starts. I have also heard about turning the petcock off as you approach your destination and there is also the rocking side to side motion while trying to start. Lots of issues starting a KLX especially when turned upside down or dropped. Typically I use the choke 1st then drain the carb if it doesnt start right away. If used every day or every other day I have no starting issues.

Also ,The klx250 runs lean from the factory running your muffler only makes it worse.
 
It does sound like you're running lean, with popping on decel and the hard starting.
What colour was the plug? Is it the right plug? Was it wet at all? What is the carbon build up like?
What kind of shape is your air filter in?
Any cracks in the intake tract? Everything seated and sealed up properly? Sometimes there may be a tiny crack in the intake between the carb and head causing a lean condition, and these cracks aren't always visible until you pull things apart.

I'd suggest taking the carb apart, cleaning it really good and then seeing what jetting you have in there. You may need to go up a size on the pilot to rich it up just enough, then spend a bit of time doing fine adjustments with things like the mixture screw and needle clip positions. How many turns out from seated is your mixture screw? If it's more than about 2 1/2 turns out it's too lean on the pilot. If you're not that far out, you can back it out 1/4 turn at a time to richen it, but there is a procedure to finding where it should be. The mixture screw isn't intended to be a "band aid" fix for proper jetting, it's a fine tuning mechanism to be used once the rest of the jetting is where it needs to be. It's handy to pick up one of those quick adjust mixture screws as they are a real pain to get to while on the bike, even more so when the bike is hot.

Last week I was having some jetting issues on the MX bike. Was running too rich in the lower RPM as I was getting on the throttle (it was running just like how 2strokes run until they "clean out"). I ended up pulling the carb off, taking it apart, cleaning everything and going down on my pilot size. Of course, once I got it back together I was very lean (shooting awesome snappy flames out the exhaust when slamming the throttle closed) so I now had a baseline and put my previous pilot size back in, and then made the proper needle position and mixture screw changes and I was good... This I learned from reading up on the net, what does what, when, how it interacts etc. There was a thread on the thumpertalk forum that was very helpful.
Eventually you'll learn to "listen" to what the bike is telling you, and experimenting is the best way to learn.
When you do carb work the importance is cleanliness. Think sterile clean. You don't want ANY dirt, grime, grease, fibers from your cleaning rag etc in any of the little ports. As you re-assemble, ensure everything is smooth and functioning, you wouldn't believe what a little piece of hidden dirt will do to a carb. I used a nice plastic bristled brush and a can of parts cleaner. Air compressor would be nice too.
 

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