The TF 250-X has been designed by world-leading Triumph Engineers and Motocross Champions to be the best in its class. Obviously it's not road legal and you'll need to fill out an enquiry form to order one, but this is a really exciting development from Triumph and should do well in Motocross championships.
The 249.95cc single cylinder 4-stroke engine has a 14.4:1 compression ratio but the power and torque are not specified. It has KYB suspension and Brembo brakes and weighs only 104 kg wet.
The machine starts at a cost of £9795 (£346 more than the equivalent KTM) but if you're going to run it competitively then there are a number of accessories you'll need to keep up with the front runners. Akrapovic titanium exhaust to reduce weight, launch control and hole shot devices, and a tuning module.
Support will be from specialist Triumph Off-Road dealerships. Currently, in the UK, those will be A1 Moto York, Norfolk Triumph, Staffordshire Triumph, Total Triumph, Triumph Plymouth, and Triumph West London.