Mika Kallio may ride with -36 degrees on his bike, but he was running a temperature of +39 degrees due to a fever at this week's private Sepang test.
However the Finn insisted on riding on each of the three days in Malaysia, despite the notorious heat and humidity.
"Mika had to leave on the first day at 4 o'clock, because he had a temperature of 39 [degrees] due to a fever," revealed Mike Leitner, team manager of the Red Bull KTM squad. "He went back, got some medicine, came back the next day at 1pm, we checked and it was still 38.
"I said 'maybe we should stop'. But he said 'maybe I can go to the doctor and get something...' and he was out on the track doing runs! Then he came this morning, his temperature was 37, his eyes were painful, but he rode again.
"This shows the passion and effort Mika puts in and we appreciate it all."
Such commitment, combined with the positive early feedback from new race riders Bradley Smith and Pol Espargaro, means KTM are hoping to hand Kallio more wild-card appearances in 2017.
The Finn, a seven-time winner in the smaller grand prix classes, stepped back racing at the end of 2015 to develop the new RC16, which he then rode on its debut at Valencia in November.
"We plan more wild-cards for Mika," Leitner confirmed. "It's not sure where exactly. But he did a really great job for us last year. It's perfect what he did because when [Smith and Espargaro] jumped on the bike in Valencia, they were really happy with the job he did."
Leitner, former crew chief to Dani Pedrosa at Repsol Honda, was speaking at the end of this week's private test at Sepang, where the six MotoGP manufacturers were preparing their machinery for the forthcoming official test.
"In general the test was really good, because we brought the four bikes for the GP riders," Leitner said. "So everything was new and all the improvements we could do from Valencia are on the bike.
"We tested different chassis and some small things, some mappings, many things. We are happy with the results, but we know it will be a big job ahead."
It may just have been the huge grandstands at Sepang, but at times Kallio's bike sounded different to Valencia and Jerez. More 'big bang'. Is it the same even-firing (screamer) engine?
"It's a constant development for us, this is clear. But in principle the engine is the same," Leitner replied.
By Peter McLaren