It does look like that 3d printed lid flows very well up to approx 8500 rpm ( the current rpm limit of your WOT runs) . Therefore, it is likely that for stock ECM's ( which detune the engine above 8000 rpm) , that lid is a more quiet option as opposed to a lidless airbox, on 300cc engines, with no performance loss.

Testing the lid with a unrestricted ECM, to redline, vs lidless, would determine overall usefulness.

 

IMO, you'd better decide exactly what you are willing to do, and not do, regarding constantly wrenching on your bike with various mods and making runs to vet the mods.

One thing is sure, the stock ECM is useless for creating high performance KLX's, no matter the displacement ( 250, 300, 351 ) .
Using the stock ECM, STP removal + KDX snorkel is all that can be done - the MCM is an additional option.
Adding a tuner (and a tune) on the stock ECM will never create high performance KLX's.

 

As to "I better decide what I am willing to do"
Eh. I'll decide at each choice if I think it's worth while or makes sense.
And I agree the stock ECM will NEVER allow the KLX to be high performance.
Even with a standalone ECM there are better options for high performance dual sports out there.
My mission statement is in my original post.

 

I hope to do that this weekend😁

 

I think i know the answer to this, but must ask - Does your equipment have a Horsepower function ?

 

"I have a Bill Blue 351 kit to install on my KLX300 but I don't have a great feeling for the fueling of the bigger bore."

The above is, I guess, your mission ? To properly fuel a 351 with a stock header and modified stock slipon ?

 

It does not have a HP function. it's intended use is motorcycle road course where the laps are timed and compared. There are addon modules for quick shifter and traction control.
I didn't have interest in the JDM ECU at first either, but decided to try if only for the benefit of the community.
Just as I'm a grey haired old man and will be untill the end, so will this always be a KLX.
I just want the best KLX I can make while learning and sharing along the way.

 

Yes. Simple as that. However I would consider a powerbomb header someday as a well as a quiet slip-on. Knowing I will not gain much there either.
If I get bored with it and run out of things to test, I may do the 402.
And then, it will still be a KLX. And to me that is a wonderful thing.
Do you have any curiosities I can help answer?

 

Well, a unrestricted / retuned replacement ECU is mandatory for creating a high performance EFI KLX.

About the JDM ECU - is this part actually in production and available to purchase ?
In fact, other than the BDSB ECU, is there any other option available for purchase ?

 

Sorry, it's been a bit. Can't share any good information, but can share the process of you are interested.
More coming, not as quick as I would like, life gets in the way.