I have a 07 klx250s. I just repiped (FMF Q4) and rejetted it. It runs really well infact better then it ever did, but it's still very hard starting. If I give it a shot of card cleaner it will start right up and after its warm it starts right up. Is there something i'm missing that I can do to get it to start when cold, or is it just because it's cold out and it only likes warm out?

Take care,
Mike

 

Common issue, particularly in colder climates.

There's a number of things that can be done. I drilled the enricher jet slightly larger, to 0.018 inches. Some remove or disable the KACR. A larger pilot jet often helps. Fresh fuel in the carb bowl is important; either drain some before starting or shut off the petcock at the end of a ride and run the carb bowl at least partly down.

https://www.kawasakiforums.com/forum...tarting-37193/

 

I have not removed the pair valve yet, could that be causing and issue as well?

 

For the stock carb, the real fix IMO is drilling the OEM starter jet as IRIDR suggested. I came up with this fix from info from Kawasaki techs many years ago for certain models of their road bikes...but it applies equally to the KLX. The factory starter jet hole/size is small. Oddly not every KLX has this problem, but a lot of them do for some unknown reason. You won't hurt anything by doing this as this jet is only operational when you have the choke engage. It's closed at all other times.

I don't find the KACR to be the problem with these bikes. Sure, it helps to have all your compression during the starting procedure, but the real problem is marginal fuel supply through the starter jet in many of these bikes...especially the older models. The KACR reduces a little stress from the starter, and I like that.

 

When the carb is set up properly, and you have good spark, cold starting should not be a problem.

With a fully warmed up engine, reset your idle speed to 1250 rpms. Improper idle speed (especially too high) is likely the single biggest reason for cold start problems.

At or near sea level, make sure the fuel screw is set to 3 turns out ( if using the stock #35 pilot jet), or two turns out if using a #40. Improper fuel screw settings will destroy cold start capability.

If the bike has not been started in 2 or more days, or it is very cold, drain a little fuel out from the bowl drain screw before attempting to start. Do not omit this very important step.

Pull choke, keep your hands away from the throttle, start it up..

Once the above is done, depending on ambient temps and fuel quality, it may not start on the 1st three second attempt, but should on the 2nd or 3rd.


Note: A KLX that will not idle smoothly and reliably at 1250 rpms (when warm/hot) has a problem - a problem that must be fixed before any assessment of cold starting can be made.

 

Edits added to post #5.
Please report your progress..

 

Cold starting is a problem for some of these carbs, even when properly set up.

Klxster doesn't like taking a drill bit to the carb. That's understandable.

But it works, and has worked for many of us without the need to have an over-sized pilot jet. I tried a bigger pilot jet and it worked for starting, but hurt low-rpm snap.

 

Cool thanks for all the help! My only other question is once its warm out how will drilling out the (choke jet) affect the starting? I'm assuming that it will be like my 1948 John Deere A tractor it's a quick on and off with the choke and it fires right off. Plus has anyone ever heard of putting a primer kit on it?

Take care,
Mike

 

Drilling the fuel jet won't affect warm weather starts much at all. If you want to see what TNC is talking about, look in the cheap hop ups link I have in my signature. If you drill, use a pin vise set up doing it by hand, NOT using a power tool. My link also links you to D. Pippin's web site with a lot of other information on the KLX250 as well. If you use the Kiehin parts you want to use that information. If you use Dyno Jet then KLXter is your best source for information.

I did the drilling and the pilot change on my bike here in Ohio at around 1000 ft elevation, I also did the MCM changes and disabled the compression release while in there doing valve adjustment too. The bike does not need the compression release. I started mine at 3 degrees F firing near instantly. I did the Kiehin jetting and it was the best thing I did with the bike. It starts near instantly when cold and is off choke in a minute or less depending on temperature. Warm weather, off in about 20 seconds.

 

Cool thanks klx678! I used a JD jetting kit per their instructions. I'm in Pa so close to your elevation in Ohio. I ordered a jewelers drill kit so I can drill the choke jet. As small of a drill bit as that is I'm not sure my drill would even hold the bit plus with something like that I would want to do it by hand as you said.