These are the known mechanical and performance specifications for your 2018 Enfield Thunderbird X 350.
Basic Specs

Engine
Displacement346.00 ccm (21.11 cubic inches)
TypeTwin spark
DetailsSingle cylinder, four-stroke
Max RPM
Compression7.3:1
Bore/Stroke70.0 x 90.0 mm (2.8 x 3.5 inches)
Valves/Cylinder
FuelingCarburettor. CV type
IgnitionTCI
Exhaust
LubricationWet sump
CoolingAir
Performance
Horespower19.80 HP (14.5 kW)
Torque28.00 Nm (2.9 kgf-m or 20.7 ft.lbs)
Top Speed120.0 km/h (74.6 mph)
Fuel Economy & Polution
Fuel Consumption
Fuel Capacity20.00 litres (5.28 gallons)
Emissions
Chassis
Frame TypeSingle downtube, using engine as stressed member
Rake
Trail
Front SuspensionTelescopic With Hydraulic Damping, 41 mm.
Front Travel130 mm (5.1 inches)
Rear SuspensionSwing arm With Gas Shock Absorbers.
Rear Travel80 mm (3.1 inches)
Seat
Seat Height775 mm (30.5 inches) If adjustable, lowest setting.
Alt. Seat Height
Total Height1,140 mm (44.9 inches)
Total Length2,040 mm (80.3 inches)
Total Width830 mm (32.7 inches)
Ground Clearance135 mm (5.3 inches)
Wheelbase1,350 mm (53.1 inches)
Dry Weight
Wet Weight195.0 kg (429.9 pounds)
Wheels & Brakes
Front Tire/Tyre90/90-19
Rear Tire/Tyre120/80-18
Front BrakesSingle disc. Two piston caliper, ventilated disc.
Front Brake Diameter280 mm (11.0 inches)
Rear BrakesSingle disc. Single piston caliper, ventilated disc.
Rear Brake Diameter240 mm (9.4 inches)
WheelsCast, 9-spoke


Comments
Brand full name is Royal Enfield. The bikes are made in India.