KLX 331 Mod on 2013 250S (Fuel Injected)
 

Just got hold of a 2013 KLX 250S Fuel injected model. I'm going to do a 331 upgrade to it. As the bike stands now it is 100% stock with just over 500 miles on it.

I have a shopping list for parts, is there anything i'm missing here to get the job done?

Kustom kraft 331 big bore kit
Two Brothers M-7 exhaust
Power Commander and auto tune kit

Surely there must be more to it than that?

Advice please. :-)

Thats pretty much all you need.... that and a nice workshop with good tools. Be sure to get the workshop manual so you know the proper torque values for the bolts and such.

I did a 300cc upgrade recently, although with an EJK controller.
I didnt even add an exhaust. Kit was installed and the controller was added and it fired up immedietly with no problems.

With the autotune kit, I think you need to be able to weld the o2 sniffer into the exhaust. I think the PCV kit comes with an o2 sensor eliminator, if not, you need to get that too. Also I hope you are prepared for the loudness of the Two Bros exhaust!

Also, its a lot easier if you get a map from someone who already has a 331kit, so you dont have to start making a completely new map. I think JoelThailand is the only guy with a PCV 331 setup as Jeffwad only runs a 300 kit? Graham also has a 331 set up, but he uses the EJK like me. Try sending Joel a PM and ask nicely if he wants to share his map :)

Some people also put stiffer clutch springs when doing a big bore. On my 300 BB I havent felt it was neccesary and you can always do it later if you think you need it...ofc you can also add the webcams if you feel like going all out!

It might also be worth it to do some airbox mods as they are fairly cheap. Uni/TwinAir filter and a KDX200 Snorkel or a completely removed airbox lid is what most people do. Cheap upgrades and certainly makes a difference.

Also if you have access to a Dyno you should do that! I am sure a lot of people on the board here would be very very interested in the results.

Good luck! Let us know about the results :)

That's pretty much it!! I had to fit stronger clutch springs, as the extra power was getting some slippage at high rpm!
https://www.kawasakiforums.com/forum...small-2899.jpg

Are you sure you can handle the obnoxiously loud TBR M7 exhaust?? The fmf Q4 delivers the same power & sounds good, except your neighbors & the police will a lot happier with you!!

Engine wise you will be ok & that's pretty much it!! I can send you a couple of PCv MAPS to play with. The only other thing is the bike is like a rocking horse made of jelly unless you weigh less than 140lbs....the stock springs are useless but that's another story.

That is actually all you really need and maybe a 20 buck Uni air filter to get some more air in the little beast.
I wish someone had told me that before I emptied a wheelbarrow of cash on mine.

This board really has a couple of pioneers when it comes to EFI KLX250 modding. Thanks to 3-4 people here documenting their modding, the rest of us have a really easy time upgrading our bikes. There is so much valuable information to be found. There is no guesswork involved anymore.

It seems there are only two mysteries left on the EFI KLX250
1) Does the 351 kit work with the stock injector?
2) How to get the bike to continue pulling after 8000 rpm. (Ignition advance I think its called)

Thanks for the replies, gentlemen.

I'm looking in to the airbox and filters, is there a particular year that will fit the 2013 KLX? Joel, I will be in contact in the near future about maps and some more information (I live in Thailand too). To be fair I actually got most of my information from this forum, after a lot of reading about changing the fuel injection system or taking it out completely and installing a carb, I just wanted to make sure I was getting it right.

Seems a little more straight forward tghan when the fuel injected model was new.

Any other input welcome, positive or negative.

Thanks again.

This is the part number for the KDX200 snorkel: 14073-1577.
Uni or Twinair foam filter can be had from many shops. Google will help you there.

And yeah, no need to replace the EFI system at all! Powercommander and EJK are both proven to work and with my experiences from the EJK, its easier than dealing with a carb.

Getting back to the 2 mysteries. I believe the 351 will work with the stock injectors. The extra 20 cc should not make much difference. The EJK has the ability to add the tiny bit more fuel you would need without maxing out the injector opening and closing time.
As for more revs, just add more cash. Simple. Webcams 101 grind will give you an extra 500 revs of pull. Mine revs out easily to 10K but the power does drop at 8.5.
Want even more? Go for Kibble white larger valves, ported head and a more aggressive Webcam grind. Need more? Get a programmable ECU to advance timing.
Still lusting for more? Go down the road to the dealer and get a 450.

My bike will rev to the 10,000+rpm limiter in all 6 gears & I haven't changed the ignition timing! 10,000rpm in top gear = 163km/h on the clock with my gearing.

If you live in Thailand then buy a Boss175 snorkel for 150 Bart (5 usd) it fits & is available at Kawasaki. Also available easily in Thailand is the DNA performance air filter from all the performance bike shops in BKK.
These shops sell KLX D-Tracker stuff & will EMS them to anywhere in Thailand from Bangkok:
http://translate.google.co.uk/transl...66%26bih%3D643, I can recommend Kittisak racing & AP shop racing but everyone on the classifieds on this forum is legit.

You will have to block off the Pair Valve if you use AutoTune, as you will get a fake 02 sensor reading if you don't.

Don't the European bikes need a clutch switch mod to rev out in the higher gears?