The three painted panels are lined out with a double parallel stripe. The thicker stripe is bisected by the edge of the painted panel, in other words, it covers the edge of the painted panel and is 3/16'' (5mm) wide. The second, thin stripe is outside it, on the chrome and is 3/64'' (1.5mm) wide. The space between the two is 1/8'' (3.5mm). The shape of the side panels is subtle and echoes the shapes around it. The most common error is to paint the panels too small whereas the factory job left quite small areas of chrome showing. The lining was done quite quickly and although beautifully executed it would not be necessarily symmetrical or even the same every time.
Original tank showing panel sizes and positions. This 3 1/4 gallon tank was fitted to all TH framed bikes, the tank illustrated from a 1939 deluxe model
Original paint 1937 250/350 tank. This tank was fitted to TL frames.
Four gallon tank (all TF frames) showing panel edges. Even when the original paint is long gone the old panels still show sometimes when repaints are stripped as here and can be highlighted as a reference.
The lining on the mudguard rib varies. For 1937 & 38 all models had the sides of the rib painted with a 3mm line. Gold lining where rib colour was Amaranth red or Plum, blue where rib colour was silver or black on the Tigers. However, in 1939 the deluxe models appeared in all black and the rib has 3 stripe, ivory white lining. A centre stripe 3/10'' (8mm) wide with parallel stripes 3/32'' (2.5mm) wide either side, with a gap of 3/16'' (5mm) between the centre stripe and the outer stripes. The Speed Twin continues as before.
The Tiger models lining with silver/black mudguards is difficult to specify. I have seen evidence of two different blues used for the lining. Some seem to have had a dark blue stripe on the tank with no blue lining to the mudguard rib, others a brighter, mid-blue stripe which also appeared on the mudguard, edging the black centre rib.
Not all the paint on the Speed Twin was in the Amaranth red. Quite a few parts were finished in black, including: both number plates, fork spring, pillion footrests, horn, voltage control box, speedo, seat frame, rear stand spring and the Lucas DC40. I have found front brake arm, rear engine plates and gearbox mounting plates in both black and red on old Speed Twins, so again, probably both happened.
There was a degree of variation to some aspects of the colour finishes over the years 1937-40. For example, it was possible to order a black Speed Twin in 1938 and 1939, and in 1940 it was actually listed as a factory option. I believe the pinstriping/lining also varied on the Tiger models (as mentioned above), possibly even black lining on early Tiger 100s. In addition, there is some evidence of black Speed Twins with gold lining.
The silver colour for the Tigers was applied as one solid colour rather than the lacquer over a base-coat so popular now. This gives a slightly dull metallic grey/silver look that is much more authentic. Similarly, the plain colours had a very distinctive look achieved by applying thinly to preserve the detail, with a deep shine rather than a high mirror gloss. The lining/pinstriping had a semi-matt/eggshell quality rather than being glossy. It is very difficult to communicate the colours themselves: The Amaranth red applied to the Speed twins has an identical comparison in an Isuzu colour called 'Red Mahogany'. The Tiger silver is more difficult as the colour deteriorates with age and comparisons with original components aren't much help. I'm sure the colour itself varied over the many years it was used, so ultimately one just has to choose something that feels right.
In 1937/38 the 'deluxe' models were finished in 'plum', a dark purplish red which has been very difficult to match. This colour was, in turn, inherited from the earlier Val Page model range.
Very close match below and this is what it looked like. Thanks Nils!
Paint finish colours according to 'Finish and equipment' specification in sales brochures:
2/1, 3/1, 3/2, 5/1, 5/2: Petrol tank black with three grey panels lined in gold. Rest black.
5/3, 5/4, 6/1: Petrol tank black and chrome with 3 single lined gold panels. Wheels chromed with black centre gold lined.
2/5, 3/5, 5/5: Petrol tank plum and chrome with 3 single lined gold panels. Wheels chromed with plum centre gold lined.
L2/1, 2/1, 3/1, 3/2, 5/1, 5/2: Petrol tank black with 3 single lined gold panels. Wheel rims black.
2/5, 3/5, 5/5: Petrol tank plum and chrome with 3 single lined gold. panels. Wheels chromed with plum centre gold lined.
5/3, 5/4, 6/1: Petrol tank black and chrome with 3 single lined gold. panels. Wheels chromed with black centre gold lined.
L2/1, 2/1, 3/1, 3/2, 5/1, 5/2: Petrol tank black with 3 single lined gold panels. Wheel rims black.
5/5, 6/1: Petrol tank black and chrome with 3 single lined gold panels. Wheels chromed with black centre gold lined.
Tiger models: Petrol tank panelled in silver sheen, lined out in blue. Mudguards black with silver sheen centre stripe lined out in blue. Wheel rim centres in silver sheen, lined out in blue.
De Luxe models: Petrol tank panelled in plum, lined out in gold. Frame, mudguards and wheels finished in black.
NB. chrome rims with enamelled centres offered as optional extra on de Luxe models.
Tiger models: As 1937.
5T Speed Twin: Entirely finished in amaranth red. Petrol tank panelled in Amaranth red, lined out in gold. Wheel rim centres in Amaranth red, lined out in gold.
De Luxe models: Petrol tank panelled in plum, lined out in gold. Frame, forks and mudguards finished in black. Mudguard centres in plum, lined out in gold. Wheel rim centres in plum, lined out in go
Tiger models: Petrol tank panelled in silver sheen, lined out in blue. Mudguards in silver sheen with black centre stripe. Wheel rim centres in silver sheen, lined out in blue.
5T Speed Twin: As 1938.
De Luxe models: Petrol tank panelled in black, lined out in ivory. Frame, forks and mudguards finished in black. Triple ivory line to mudguard centres. Wheel rim centres in black, lined out in ivory.
5T Speed Twin and Tiger 100: as 1938.
3T deluxe: as 1939 deluxe models.
T85: as Tiger 100
6T Thunderbird: All in thunder blue.
5T Speed Twin: All in amaranth red.
T100: Petrol tank in silver sheen, mudguards silver with black rib. Wheel rims with silver centre lined blue.
As 1950 except: 6T Thunderbird now in polychromatic blue
Petrol tank silver sheen panels lined in blue