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Only $10 for all 2026 SX, MX, and SMX series.
My practice princess friends run U4.4 designed for riders and racers who are not restricted by fuel rules . They jet their bikes for it; the FI bikes will adjust automatically to that is better.
U4.4 REG contains 7.5% oxygen and uses a higher-octane blend to support strong performance in both stock and modified engine combinations.
I'm cheap and only run the stuff at Mammoth.
Virtually none of the dirtbike EFIs are closed-loop designs that can adjust themselves ideally to conditions.
FI bikes do not automatically adjust to fuel differences unless they have an O2 sensor. No MX bikes have O2 sensors. KTM is just adding knock sensors to the 2027 FE and 2028 regular 4t bikes.
O2 sensor on a 2 stroke would be useless in a week due to the oil....
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KTM testing a new 2 stroke. It has an O2 sensor. Might just be for testing ECU maps, or looking into more refined fueling and more advanced mapping options.
Pretty sure in years past, photos of test models have had O2 sensors frequently. But I think people are missing the points in the last few posts. No FI mx bike currently has any way of adjusting fueling based on A/F ratio.
There were a few posts clipped from this morning?
That's likely an EGT sensor. As @harescrambled mentioned above, O2 would easily foul.
Not sure why the 2T EFI moto bikes don't come with EGT sensors like snowmobiles (maybe, as shown, the next gen KTMs will - but probably was just for R&D). I had a 22 EC250 and struggled to get 1 map that would work well for trail riding, and also for faster/sprint sections. I believe the pipe temp and appropriate changes to fueling would improve that.
It looks like a Bosch O2 sensor...
It also has a knock sensor....
Oil will destroy the sensor eventually, but that doesn't matter for testing, KTM would swap it for a new one.
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