All data that you see below is from the Royal Enfield site as of 08 Feb, 2005. Don’t worry, nothing much has changed in terms of the Thunderbird specifications over the last few years (and this data is pretty much upto date, till this model went out of production many years later.)

The only few things that’s changed from what my motorcycle specifications to the 2nd generation Thunderbird are:

1. Thunderbird comes with a different ignition system.
2. The paint scheme has changed.
3. It now has auto start.

They’ve tried, but the vehicle characteristics pretty much remain the same. Nothing much can change the quirks and tantrums of the basic Bullet platform I guess.

TECHNICAL SPECIFICATIONS*:
Engine	Single Cylinder, 4 Stroke, Air cooled	Awaiting Image
Displacement	346 cc
Bore x Stroke	70mm x 90mm
Maximum Power	18 bhp@ 5500 rpm
Maximum Torque	2.75 kg-m @ 3500 rpm
Transmission	5 gears
Ignition	Electronic CDI
Carburetor	Constant Vacuum (CV)
Dimensions
Length	2120 mm
Width	750 mm
Wheel Base	1370 mm
Ground Clearance	140 mm
Tyres
Front	3.25″ X 19″
Rear	3.50″ X 19″
Electricals
System	12 V
Head Lamp	45/40 W
Braking System
Front	Drum 7″ dia. Twin Lead Optional – Disc Brake 280mm
Rear	Drum 6″ dia.
Maximum Speed	120 km/hour
Features
A powerful 350cc, 4 stroke bike, the Thunderbird, is India’s ultimate outdoor bike. Constant vacuum (CV) carburetor for easy starts 155 mm travel telescopic front fork Fuel efficiency of around 40 kmpl under standard test conditions Easy access control switches and hand lever controls Ergonomic stepped seat and comfortable backrest for the pillion Wear indicators in the front and rear brakes Duck bill side stand for ease of operation
*All data from the Royal Enfield site as of 08 Feb, 2005.

Go here for the AVL 500 specifications.