Hi friends,
I have stock EFI klx250, 2022 model year. I live in Bali, so it's Indonesian spec. I think it's the same as latest years of US and Europe EFI 250 bikes - 22hp@7500, 21Nm@7000. I'm planning to gradually add some mods and validate how they affect performance. Dyno runs a cheat here ($15), so I'm planning to document each mod impact with dyno measurements

.

To start with I decided to compare

1. stock bike and
2. bike with KDX snorkel + clutch switch mod.

I found results interesting:

1. despite people report some magic gains of the clustch switch mod (apart from removing speed limiter) I don't see them.
2. KDX snorkel adds some torque (which I felt before dyno). But it's not that huge torque increase at full throttle. I believe it's due to the fact that "dyno butt" measures mainly during closed loop where ECU can add more fuel based on lamda. As you can see at full throttle the AFR is more lean (13.8:1) compared to stock AFR (which I believe is 12.5:1 - 13:1 according to graph)
3. So adding more fuel should help to get more out of the better intake.

My plan for the next step:

1. Add ~6% more fuel using NTC 2.5 kOhm (see calculations here). This should bring AFR back to 13:1.
2. Modify end cap of the stock exhaust - replace the tip with 2.5cm stainless steel pipe like
   here
3. Go to dyno and see what it gives

Later plans are MCM and 300cc AHL hit with bigger injector.

I'm open to suggestions here! Please leave a comment on what would you like to see measured.

Cheers,
Dmitry