hi, just bought a kLX 250, 2007 model and it wouldnt start when cold, i noticed that if i pulled the choke on when it ran i noticed that it didnt make much difference, i read all the suggestions about a fix, i have now fixed it and i am entering my end result as i cleaned the carby several times beforehand and still wouldnt start, it had dried up petrol at the bottom of the bowl when i first took it apart, so for the 3rd time i took it apart and this time i submerged the body in KBS Aqua clean a water based cleaner for 30 minutes, then i washed it in hot water then repeated the process to make sure to dissolve the stuff which was causing the blockage, then i soaked it in petrol for 2 hours and using compressed air i went about blowing out the passages, the one to watch is the 2 brass jets at the airbox end on the carby throat, i repeated the process several times over 30 minutes, i filled up the carby throat and watched as all the vent holes jets drained the petrol away, which they did, i reinstalled the carby and it now starts when cold and the choke works better, it just about stops the engine when briefly pulled on, hope this info helps someone, thanks.

 

It's all good

I think there's a technique using warm water, vinegar and maybe baking soda as well just in case there's no Aqua clean handy

 

Another cleaning method is to clean the carb parts with Pine Sol that's available at your local grocery or hardware store.
Cleans the carb parts very well and when done they look like new.
Then blow out all the passages with compressed air.

 

+1 pine sol works very good.