This is a very interesting development.

It would certainly seem that you've found a ECM that fully restores the upper RPM power band. I completely understand your excitement. Everyone that has taken a stock (carb'd) KLX to one of the lidless mod combos, has experienced the exact same thing.

I assume you'll use a proper rear tire for the dyno run - I remember your post proving that dyno'ing with a knobby tire is a total waste of time and money.

It is possible ( and makes sense ) that a racing ECM is "set up" for a lidless airbox. Just know that 30+ HP can only be made with a lidless airbox.

 

Great find TSC!

Are you running the ECU with or without the addon fuel controller you were running with the stock ECU?

Thanks,
Tim

 

ECU + fuel controller. I will check on dyno soon if bigger injector also needed (might be as according to fuel controller numbers the injector duty cycle at high rpm approaching 90%).

 

Hey folks! Good news here. We have 31 hp at rear wheel!
I finally found recipe how to make bike work properly. All that with OEM(!) unrestricted ECU. Which is absolutely great as it gives you all the reliability, knock monitoring, etc.
This is 2.5 hp increase from my previous best run with standard restricted ECU. But the most important is that bike maintain 28-31hp within entire upper range 7 - 10k rpm.

Bike set up is really simple

1. full custom exhaust with megabomb style header
2. secondary throttle plate removed
3. Airbox from old (1997-2007) klx300r. In theory should be more aerodynamically efficient. But not sure if really matters - new pink chart is very close to what I had before with standard airbox.
4. piggyback fuel controller

Dyno chart:

1. red (30.93 hp) - new unrestricted ECU + airbox lid off
2. blue (28.82 hp) - new unrestricted ECU + airbox lid on + KDX snorkel
3. pink(28.68 hp) - old restricted ECU + airbox lid off

I use smoothing=2 on these charts. Without smoothing the best run was 31.1 hp.

 

Great results.
Your AFR goes too lean @ 6800 rpm, and stays lean until about 9600 rpm. More power is available if AFR is kept between 12.5 - 12.8 .
Yet another data set proving that the KDX snorkel destroys power levels - compared to a lidless airbox.

The problem with all this - How can the membership replicate your mod combo ?

It seems your custom-built exhaust system performs well - I feel sure the Barker system will produce at least the same performance.
Yanking the lid off the airbox is a no-brainer for anyone to replicate.
Yanking the secondary throttle valve is a no-brainer as well.
However, your ECM and choice of fuel controller are BIG question marks - and they are only way your power levels can be duplicated.
How does a member purchase those two devices ?

 

The recipe is simple

1. remove secondary throttle plate
2. remove airbox cover
3. install full aftermarket performance exhaust. I think Barker / FMF will work more or less same as mine. Any free flowing muffler (Delkevic?) without head pipe should be also ok, but it will give less power (maybe 1-2 hp less). I feel head pipe is important. If you want full system like mine - I can order and ship, $300 for the full exhaust incuding heatshield. Can ship anywhere.
4. Install fuel controller. I've already made plug and play version for KLX250/300 which connects to native sockets. $150. I can produce these . I will ship anywhere. I will put fuel settings. Fuel settings can be adjusted using phone and bluetooth. Alternatively one can use EJK (it sucks and i don't recommend it!) or PowerCommander. At the moment my fuel settings are following: 0-2500 rpm +40% fuel, 2500 - 6600 rpm + 35% fuel, 6600 - 12000 rpm + 20% fuel.
5. Install unrestricted ECU. These ECU are not very common and can be found on Japansese versions of the bike (and some Indonesian models). As mentioned before in the thread one must look for KLX250 ECU which produce 24hp@9000rpm and have ignition 10 degrees at 1300 rpm to 39 degrees at 11000 rpm. I have 2 spare tested ECU at the moment and can sell $300 each. Supply is very limited, it was hard to find them. I can't provide part numbers at the moment - I hope everyone could understand as I've spent some money on research, dyno and took the risk purchasing these ECUs. Anyway $300 is at least 2x cheaper than buying new ECU from Kawasaki.

 

One more thing! I've tested bike with db killer in the muffler. Which makes outlet 25mm in diameter. Maybe additional fraction of horse power could be found by removing it.

 

Ok, it seems that acquiring the correct ECU is the "sticky point" for 31+ hp. So let's explore this further..

While @da2 and @tsc are the "go to" peeps on this, the goal is to acquire a Japanese ECU for a early ( 2016 as per @da2 ) Japanese KLX250 that spec's out as " 24hp@9000rpm and have ignition 10 degrees at 1300 rpm to 39 degrees at 11000 rpm" .

As I understand the situation, with @tsc having a 300 bb kit on a older KLX250, the big question is whether these ECU's are plug compatible with the newer KLX300's ?

Once this ECU issue is fully solved, and with a @tsc exhaust system and tuner in hand, the performance increase is so extreme as to fundamentally "change the equation" regarding owning or buying a KLX300.

 

Klx300 EFI and klx250 EFI are exactly same bike except engine displacement. Wiring, Injector nozzle, throttle body - all the same. Klx250 ecu is a direct fit.

 

It is too bad that there isn't anyone who has developed software to change the fuel and ignition mapping in the ECM. Woolich Racing https://www.woolichracing.com/ is a major player in that field and it wouldn't hurt for the efi folks to reach out to them to see if they could help. Piggyback controllers are not the best way to fix this.