Power increase
Reworked ignition and injection maps for more power and sharper response, tuned to your bike's original software.
Loading
Keihin 79641031000 · order online
Software tune for your GasGas EX 250F (2021–2024) with the Keihin 79641031000. We adapt the tuning file to the original software read from your ECU, and you choose the functions and how strong they are.
Configure it your way: pops & bangs, power increase, party mode or multi-map. You choose what goes on and how strong it is.
Price from€150
Configure now
Bike & ECU
Cross-country, same engine as the MC; Figures from the identical engine of the GasGas MC 250F
KTM does not publish exact power figures for its competition engines, including those in the Husaberg and Husqvarna models. The figures are guide values for the unrestricted stock output from dyno tests and the motoring press, or from the identical engine.
What the tune does
Everything runs in the software of your stock ECU. We adapt the file to the original software read from your bike. Every function has its own strength setting, and it does not change the price.
Reworked ignition and injection maps for more power and sharper response, tuned to your bike's original software.
Pops and crackles on the overrun, but only while you hold the throttle slightly open. With the throttle closed it stays largely quiet; at high revs it may still bang.
Motorsport only · not road legal – Learn more
Hard cut at the rev limiter: ignition is cut and the ignition timing retarded, giving bangs and flames from the exhaust. You pick the sound via the hysteresis, from “Brrrrr” to “Boom boom”. The stock cut-off stays above it as a safety net. Increased thermal load on header and exhaust.
Motorsport only · not road legal – Learn more
Spread the options freely over all 4 maps and switch with a map switch, e.g. map 1 stock, map 2 power, map 4 party mode.
Comparison
| Function | Stock | With Efimow tuning |
|---|---|---|
| Pops & bangs on overrun | – | Character in 5 steps, from “quick & light” to “slow & strong” |
| At the rev limiter | Stock cut-off | Hard cut with retarded ignition, sound in 5 steps from “Brrrrr” to “Boom boom”; the stock cut-off stays on top |
| Ignition & injection maps | Stock calibration | Reworked, calibrated for Super 95 or Super Plus |
| Maps on a switch | Stock layout | Up to 4 freely assignable maps (multi-map) |
| Peak power / torque | 42 hp / 26 Nm | approx. 43 hp / 27 Nm (guide value) |
Pops & bangs and party mode: motorsport only, not road legal. Tuned figures are guide values, not a measurement of your bike.
Dyno
Stock 42 hp / 26 Nm → with tune approx. 43 hp / 27 Nm
The tuning curve shows typical values (+4 % in the mid and upper rev range) and is not a measurement of your bike. How much you actually gain depends on its starting point: restricted homologation or open, exhaust, air filter.
Stock curve: typical shape calculated from the peak figures on this page (41 hp, 26 Nm). There is no dyno curve for this model.
Requirements & hardware
Map switch in development: pre-order now, shipped as soon as available; we let you know by email and send it to you for retrofitting. Stealth: hidden in the fairing, 4-way rotary switch, not waterproof. Clean: on the handlebar, aluminium, 2 buttons, IP67. KTM’s stock switch (part number 77239974200) works too, with map 1 or the map picked on the base-setting rotary switch. Coming soon as well: switching maps from your smartphone.
Process
Configure
Your EX 250F is already preselected below. You pick the model year, options, strength and, with multi-map, what goes on each of the 4 maps.
Check the sticker & order
Before checkout you compare the number on your ECU. You can pay online or in cash.
On site or ship it in
An appointment with us in Stödtlen on your preferred date, or send us the ECU by post. You share the tracking number via the link in your order confirmation.
Read, adapt, program
We read the original software, adapt the file to it and program your ECU. By post the whole thing takes approx. 3–7 days, including shipping both ways.
On site with us
Ship in the ECU
Why Efimow
Fits
GasGas EX 250F, model years 2021–2024, with the Keihin 79641031000 ECU.
Other models with this ECU
Your benefits
Motorsport only
Pops & bangs, party mode (hard cut) and the power increase are intended for motorsport and are not permitted on public roads. Unburnt fuel in the exhaust stresses exhaust valves, header and silencer more than the stock calibration; party mode increases the thermal load on the exhaust. Changing the engine software voids the vehicle's type approval. Learn more
FAQ
GasGas EX 250F is preselected
Pops and crackles on the overrun, but only while you hold the throttle slightly open. With the throttle closed it stays largely quiet; at high revs it may still bang.
Reworked ignition and injection maps for more power and sharper response, tuned to your bike's original software.
Hard cut at the rev limiter: ignition is cut and the ignition timing retarded, giving bangs and flames from the exhaust. You pick the sound via the hysteresis, from “Brrrrr” to “Boom boom”. The stock cut-off stays above it as a safety net. Increased thermal load on header and exhaust.
Spread the options freely over all 4 maps and switch with a map switch, e.g. map 1 stock, map 2 power, map 4 party mode.
Pops & bangs and party mode mean unburnt fuel in the exhaust, which stresses exhaust valves, header and silencer. All functions are intended for motorsport and are not permitted on public roads. Learn more
GasGas EX 250F
Keihin 79641031000
Choose at least one option.
How does the tune get on?
Now choose the year.