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Today I've made another dyno with following mods on top of KDX snorkel
2.5kOhm NTC in series in IAT to add more fuel.
Modified stock exhaust muffler. I've removed "straw" end pipe and replaced it with 2.5cm stainless steel pipe. I followed the process shown in this video. It was quite difficult to remove the stock end pipe from the muffler - took about 30 minutes back and forth. I'm very happy with the sound though - it's still quiet (I measured 90dB), but more pleasant. You can check my video here. I do feel exhaust flows much better - the air stream pressure after exhaust tip is much stronger compared to stock straw.
The dyno (top-down on the chart):
Red - KDX snorkel, modified exhaust, NTC
Blue - KDX snorketl, modified exhaust (no NTC/IAT modification)
Pink - KDX snorker
Observations:
According to AFR chart NTC added less fuel than I expected. AFR is basically just little bit rich.. Maybe the relation between IAT and additional fuel is not that linear I assumed.
Without fuel correction there is no power gain in modifying exhaust. Power torque lines are basically the same.
You did absolutely BEAUTIFUL exhaust work!
It sounds SO much better and you kept the original factory look. It's likely that with fuel tuning you can realize some power gains. I also experiment and modify my exhaust so I know how much fun it is.
klx300 and 250 ebu are not same.
Indonesian manufactured klx are castrated.
I hawe japanse manufactured klx250s
Year 2016
iInjected
24 hp at 9000 rpm
Ignition at 11000 rpm 39 degree.
klx300 and 250 ebu are not same.
Indonesian manufactured klx are castrated.
I hawe japanse manufactured klx250s
Year 2016
iInjected
24 hp at 9000 rpm
Ignition at 11000 rpm 39 degree.
I would not call it castrated. 22hp is pretty typical for EFI klx250.
There is also ninja 250SL here which use same 250cc engine, but produces 28hp/22.7nm torque. I've done some research about differences of the klx and ninja 250sl engine set ups. Interestingly even camshafts are same (or very similar)! Part number for camshafts for 2021+ klx300r and 250sl are same.
The differences I found so far - larger 38mm throttle body on ninja and possibly different ignition system.
I would not call it castrated. 22hp is pretty typical for EFI klx250.
There is also ninja 250SL here which use same 250cc engine, but produces 28hp/22.7nm torque. I've done some research about differences of the klx and ninja 250sl engine set ups. Interestingly even camshafts are same (or very similar)! Part number for camshafts for 2021+ klx300r and 250sl are same.
The differences I found so far - larger 38mm throttle body on ninja and possibly different ignition system.
28 horsepower is really good for a 250, except the Ninja's curb weight is 379 pounds.
I'll gladly take the reduced engine power as my curb weight is a nimble 288 pounds. That's 91 pounds, or 24% lighter. On small bikes, weight matters. And reducing it has the same effect as adding more horsepower.
And you cant add more fuel whit temperature sensor
Its oxygen sensor here.
Its open loop and closed
Maybe for testing you need plug off cooling temp sensor.
then your ebu turns in to open circuit mode.
If its works then you need another cooling way
Nice work
Theorerical its rich at high rpm because ignition timing .
Can you tell me your ecu part number?
Not sure about exact number. You can try find in catalogs - Indonesia klx250, 2022.
But as per user manual ignition is 5 degrees at 1300 to 34 degrees at 11000. So it's retarded compared to Japanese 39 degrees.
12-31-2023, 04:42 PM
