Hello! I am Jason from Greece and I recently bought a Kawasaki Klx 250, which had been bored to a 300cc cylinder and piston.

Bike also has a Power Commander III (412-410) but it wasn’t tuned properly by the previous owner.

For that reason I brought the bike to my local dyno tuner, which only made matters worse (I paid 150€)

Bike has trouble starting up, idling when cold, it stalls ,it misfires and the exhaust pop very weirdly sometimes when I close the throttle.

Furthermore, it seem like it doesn’t produce much power after 7.000rpm (as shown by the dyno graph)

Does anybody know how I can tune this thing properly? I’ve read numerous threads on this subject but I don’t know what to do.

-Should I tune the Power Commander properly? How can I do that?

-I’ve also read about the ejk controller. Does that work? If yes is it a plug and play solution, or an expert has to tune it?

-I am also thinking about returning the bike to its stock form(since I have the original 250cc cylinder) but this is very costly and I like the extra power.



Any help would be very valuable to me.Thanks!

 

1. Make sure there are no issues with the intake tract as ALL of your symptoms can be caused by an air leak in the induction tract.
2. Dyno tuning with the PCIII is childsplay. Any dyno shop can perform this simple procedure.

I suggest that you perform all testing procedures in order to find any air leaks, then find another dyno shop. For wide open throttle operations, tell the shop that you want AFR kept between 12.6 - 12.8 to one.

 

Thank you for your reply.
Do you know how I can check for any air leaks?

I've spoken to many dyno shops here in Athens:some say the don't want to take care of it,some say the PCIII isn't enough to tune this modification and the dyno shop I went to couldn't tune it properly (even though they suppose to be very skilled) which is why I am confused about the big bore,since I thought it would be relatively easy to tune it properly

Is the PCIII enough to tune it,or do I need a new ECU?

 

One test is to carefully spray starter fluid/carb cleaner around the intake tract while the engine is warmed up and idling. Any change in engine speed (etc) indicates a leak.

The PCIII is quite capable of "handling" the 300cc Big Bore. It has the ability to double the stock fueling .

And a "skilled" dyno shop was not able to tune it ? Wonder why.. Could be because your engine has something wrong or several things wrong with it ?

At any rate, thinking you can solve your problems by putting in a smaller piston (250cc) is completely flawed logic. Doing so will not affect your current problems.
The stock 250 EFI system - without any tuner connected - should properly fuel idle, and part throttle operations on your 300 ( assuming the intake and exhaust tracts are stock) .

There is probably no way you are going to get this solved yourself - I sense you are not skilled in EFI fueled ICE. A relationship with a Kawasaki mechanic and a dyno shop is probably the best option for you.

 

Jason, I have a 2018 KLX 250 with EJK controller. Installed 330 cc big bore but had same fueling issues. I tried everything to to avail. I have not heard anyone getting a fuel injected KLX 250 with big bore to run properly. Your best bet is to re-install the 250 cylinder and piston. That’s what I ended up doing.

freekdaddy

 

Google Keng engines. This guy has been fabricating klx 402cc kits for carb or efi bikes. He’s got it figured out with a bigger injector. He’s on face book. Don’t be discouraged just yet… remember Kawasaki has the efi klx300 in showrooms on dealership floors

 

Just got back from Keng’s in Chiang Mai. He was super helpful. Had his 355 kit installed and rode it back 2500km to Kuala Lumpur no problem. 100% vouch for Keng and I’m pretty sure he’ll be able to help you out.

 

Check these 2 threads -
- https://www.kawasakiforums.com/forum...olution-47852/
- https://www.kawasakiforums.com/forum...uestion-47485/

It looks you can use bigger (260cc) injector and optionally NTC thermistor (if more fuel is needed) to get stock ECU work with 300cc block. At least this is what I'm planning to do.

 

Hi.
I did a AHL 292cc and bought a 270cc injector from ebay. It is listed as Suzuki part no.15710-21H00.
All for less than €250,-
I took out the first plate at the EFI body and KDX snorkel.
Just little more than 1000km on- but until now it runs nice.
Have to check spark plug for color by time.
I guess it is a cheep solution for an easy big bore assembling.

 

Thanks for sharing and confirming this set up! Few questions
- Do you mean 299cc AHL kit (not 292)?
- Did you try this set up with and without first plate? Does it run better without first throttle plate? Could you please provide little bit more details on that?