Unpredictable weather forecasts affected the entirety of the second eight-hour session of the 2023 MotoGP pre-season, with a damp track greeting the field when the pitlane opened at 10am local time.
While all bar HRC test rider Stefan Bradl and Yamaha test rider Katsuyuki Nakasuga would eventually put times on the board, with Pramac's Martin leading the way on a 1m58.736s, it wouldn't be until the third hour of the session that any meaningful running was done.
KTM's Jack Miller was first out on track in the morning while the circuit was damp, with the rider he replaced – Miguel Oliveira, now at RNF Aprilia – setting the pace in hour one with a 2m11.323s.
Only four times were put on the board in the first hour, with Miller taking over at the end of hour two with a 2m01.523s, though still only four riders had registered times.
But by now the track had dried sufficiently enough to tempt a swell of activity in hour three, with 2021 world champion Fabio Quartararo shooting to the top of the order on his factory Yamaha with a 1m58.897s.
Quartararo put some miles on Yamaha's new ground effect lower fairing, as he continued evaluating a new chassis and engine.
Come the end of the fourth hour, Pramac's Martin had found a 1m58.736s on his 13th lap of the day to take over at the head of the timesheets.
Not long after this, rain began to fall again at Sepang and track conditions deteriorated, with Martin getting caught out by a damp kerb and crashing.
The arrival of rain forced most back into pitlane, with only a handful of riders heading out onto the wet track across the last few hours as the session came to a close at 6pm local time.
Oliveira was second fastest as he continues to adapt to the Aprilia, the Portuguese rider improving to a 1m58.839s to shadow Martin by 0.103 seconds.
Pol Espargaro rounded out the top three on his GasGas-branded KTM, with the Tech 3 rider 0.042s behind Oliveira.
Quartararo was fourth ahead of reigning world champion Francesco Bagnaia, who was confident after the opening day of running on Friday that Ducati was in much better shape with its new bike than it was at the same stage last year even if he felt the GP23's engine was still a bit aggressive.
Raul Fernandez completed the top six on the second of the RNF Aprilias, with VR46 Ducati rider Luca Marini heading Alex Rins, who led the Honda charge on his LCR-run RC213V.
Enea Bastianini on the sister factory Ducati and KTM's Brad Binder rounded out the top 10, with Franco Morbidelli 0.059s outside on the second of the Yamahas.
Marc Marquez was 13th on the factory team Honda as he continued HRC's expansive test programme, the eight-time world champion admitting after day one that the 2023 RC213V was "still far from the top".
New teammate Joan Mir was 16th as he continues to get to grips with the Honda, while Alex Marquez was 17th on the Gresini Ducati ahead of the first of the Aprilias of Maverick Vinales.
Aleix Espargaro only completed 26 laps on day two having suffered a crash during the session, which left him down in 20th on the timesheets on the second Aprilia.
The first pre-season test of 2023 concludes on Sunday, with the track opening at 10am local time.
| Pos. | Rider | Bike | Time | Gap | Laps |
| 1 | Jorge Martin | Ducati | 1'58.736 | 17 | |
| 2 | Miguel Oliveira | Aprilia | 1'58.839 | 0.103 | 52 |
| 3 | Pol Espargaro | GASGAS | 1'58.881 | 0.145 | 29 |
| 4 | Fabio Quartararo | Yamaha | 1'58.897 | 0.161 | 34 |
| 5 | Francesco Bagnaia | Ducati | 1'59.067 | 0.331 | 35 |
| 6 | Raul Fernandez | Aprilia | 1'59.112 | 0.376 | 35 |
| 7 | Luca Marini | Ducati | 1'59.118 | 0.382 | 50 |
| 8 | Alex Rins | Honda | 1'59.163 | 0.427 | 28 |
| 9 | Enea Bastianini | Ducati | 1'59.194 | 0.458 | 32 |
| 10 | Brad Binder | KTM | 1'59.230 | 0.494 | 30 |
| 11 | Franco Morbidelli | Yamaha | 1'59.289 | 0.553 | 44 |
| 12 | Marco Bezzecchi | Ducati | 1'59.361 | 0.625 | 31 |
| 13 | Marc Marquez | Honda | 1'59.450 | 0.714 | 36 |
| 14 | Fabio Di Giannantonio | Ducati | 1'59.502 | 0.766 | 40 |
| 15 | Johann Zarco | Ducati | 1'59.503 | 0.767 | 36 |
| 16 | Joan Mir | Honda | 1'59.632 | 0.896 | 36 |
| 17 | Alex Marquez | Ducati | 1'59.747 | 1.011 | 36 |
| 18 | Maverick Vinales | Aprilia | 1'59.770 | 1.034 | 35 |
| 19 | Jack Miller | KTM | 1'59.859 | 1.123 | 47 |
| 20 | Aleix Espargaro | Aprilia | 2'00.017 | 1.281 | 26 |
| 21 | Takaaki Nakagami | Honda | 2'00.223 | 1.487 | 32 |
| 22 | Cal Crutchlow | Yamaha | 2'00.354 | 1.618 | 41 |
| 23 | Augusto Fernandez | GASGAS | 2'00.732 | 1.996 | 32 |
