I have a 2012 250cc D-tracker and it start no problem when cold but once I ride it for a while and it gets hot, if turned off it will not start again until the engine cools off. Once the engine is cold it starts again no with no problems. I brought the bike to a Kawasaki dealership but they can not find the problem so I need help form the experienced people on this forum.

 

100 people have viewed my post and no one has experienced the problem?? Help..

 

I would check valve clearances first. If they are all in spec, I'd ohm the coil next. Primary windings should be between 0.17-0.23 ohm and secondary winding should be 5k-7.6k ohms. If that's all in spec, I'd suspect the carb.
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Thanks very much HemiBob for your suggestions. I will check all of your suggestions thanks. I did replace the carb last year, The bike does sit 1-2 months sometimes without getting started but as I mentioned the bike starts and runs fine until it gets hot. It does not stall when hot, but if I turn if off, say to go in a shop or something then return and try to start it will just crank over without starting but if I wait 20-30mins it starts fine again and runs fine..it is a strange one.

 

Crazy as it may seem, it sounds like vapor lock in the carb. Never heard of it on a bike like the KLX though. Some Honda V-4 would have it happen, cars could too. If there was some way the fuel could overheat in the float bowl it could happen. Long shot though.

One other thought. Is it still stock jetting? If so the lean nature might be a problem starting. It could also be an issue if you are trying to use the choke on a warm engine, that will cause flooding. If it is stock go to the link KLX250S Home Page and do the jetting as noted in the carb mods continued, for sure the richer pilot jet eases starting. My brother and I did the mods as listed, doing richer mains because we are around 3000 ft lower elevation than his location. It was a "plug 'n' play" for both of us, worked fine right off. If jetted, make sure the pilot jet isn't bigger than that listed on the site.

 

I have not owned a KLX in several years but your symptoms match a failure in the crank position sensor of a Honda NT700. For example, it would be running fine then after stopping to fuel up the bike would not start until it cooled down. Basically the engine did not know when to fire so it defaulted to no fire. The sensor is a coil and likely after cooling it made continuity again. On the NT they were not difficult to replace.
So you might look at something similar on the KLX like an intermittent electrical sensor. Good luck, intermittent can be difficult to find for sure.

Arknt

 

KLX678 - thank you for your suggestions. I will look at the jets. Yes it is a stock bike and it has run for the past 5 years no issue. It just started about 2 months ago. Very frustrating as it starts perfect every time as it always has and now it just start after no mods to the bike??

 

Thank you ARKNT. Yes I was thinking along the same lines and as you mention an intermittent problem is very difficult to track down sometimes.

 

@SeeDeep Sorry it wasn't that easy. Hope you find the issue. It might be worth taking to a dealer service department for analysis. Sometimes it's worth the money to save time and other money. I've seen riders chase electrical issues all over the place and spend hundreds with no results. A good service department can do some testing and may find issues relatively quickly. If you do, remove all bodywork yourself, possibly including the fuel tank if they have a small tank to hang off the side of the bike for testing. No sense in paying for what you can easily do. I took in a scooter minus bodywork for a fuel system test. Was 1/2 hour and they said fuel pump. A new one fixed all.

 

If the problem is repeatable you might set up to check to see if it is electrical as I mentioned on the NT. That would limit things some. Maybe have an extra spark plug handy and when it shows a no start, check and see if there is spark. (hopefully done close to home)
If no spark you aren't done but have limited it down quite a bit.

Arknt