Tractor test: Kubota M128X With average UK tractor size coming in at 138hp (2008 sales), it could be argued that Kubota’s 94kW/128hp M128X flagship is still a little deficient in the motor muscle department. Not at all, counters Kubota, which reckons its biggest but still compact ‘M’ ticks all the boxes for most mixed farming applications. Our test assesses M128X performance at the test station and in the field