Vincent Comet Tachometer Revolution Counter Table for reference
No.
Model No.
 range
 Drive
rotate
 Ratio
 spec
 light
 bezel
 needle
type
 applications

RC. 83








RC.87
ccw






RC. 95
 8000


no
 std
 plain

RC. 103
 8000
 ccw
 4/1
 BC
 yes
 std
 oval
 Douglas 90, Grey Flash

RC.109
ccw






RC. 115
 8000
 ccw
 4/1



Black Lightning w/yellow graphics












RC.1302/00
 10000
4/1
yes
 flange
 oval

RC.1303/03
ccw






RC.1307/00
 10000
 ccw
 4/1
yes
 std
 plain

RC.1307/01
 8000
 ccw

yes
 std
 plain

RC.1307/02
 10000
 ccw
 2/1

std
 plain

RC.1309/00
 8000


yes
 std
 plain

RC.1314/01
 12000
4/1

flange
 plain
Smiths codes
A - indicates 120mph with trip.
B - indicates chrome bezel, black dial, internal lighting
C - indicates 8000 RPM, 4:1, anti clockwise rotation.

Craig, I do not believe that an electronic tach that looks original is available.The Flash did not use Lightning instruments. The production Flashes used white numeral 0 to 8k  Tachs and the  five TT Flashes were equipped with 0 to 10k white numeral tachs.
The specification was:
                                         Code            Spec.
speedometer (miles)           S.433/3/L     AB
Tachometer                        RC.103        BC
The letter
"C" indicates 8000 RPM, 4:1, anti clockwise rotation.
"B" indicates chrome bezel, black dial, internal lighting
"A" indicates 120mph with trip.
The angle drive is 36362/1 or 70549/1 which are 2:1
You may have difficulty finding an RC.103, but you can buy almost any similar tach like a 1309 used on Nortons and I believe Nissonger can convert it from 2:1 to 4:1 anti clockwise, or so I am told.
David

Hi David, This is great information, if you dont mind, i would like to keep it on my Comet Pages.I wanted an electronic tach just for accuracy and ease of hook up.I see the vocspares sell a PR32/1 , do you know if this is complete with correct machined ATD cover? tach cable seems easy enough. there is a 1307 tach, 4/1 on ebay...how do you tell rotation? can it be converted to 8000 from 10,000?When you say anti clock wise, does the needle turn anti clockwise as well? thanks  Craig

At 10:32 PM 8/19/2010, you wrote:
Craig,
PR32/1 is just the angle drive. The other parts you need are listed in Fig. 23 of KTB.
RC1307/00 is a good one. It is 4:1, anti clockwise with a light. I would use it as is, but if you are going to have Nisongers rebuild it they can probably change the face and make it an 8K.
The rotation refers to the to the rotation of the inner cable not the sweep of the hand, but it is a good question, because the wrong rotation will turn the hand the wrong way.
The cable is listed as being 2' 3-1/2".
David
Part Number
 description
graphics
617
 2BA x 1" screw, hex head set
 4
841
 2BA x 5/8" screw, round head
1
842
 2BA washer, single coil spring
1
845
 3/16" x 1/2" bsw screw cheesehead
 2
1021
 2BA washer,  lock tab
 4
E 54
 magneto pinion nut
 1
ET 219/1
 rev counter drive cover
 1
ET 222
 rev counter drive dog
 1
ET 223/1
 rev counter drive boss
 1
ET 224
 rev counter drive fork
 1
PR 32/1
 Smiths drive BG 1508/01, 2-1, reversing
 1

Basic tables as a start below thanks to http://omega-13.com/smiths/smiths_1.htm
Smiths Chronometric Competition Tachometers
Part Number Max. Revs. Ratio Direction Needle Application






R.C.53
 8,000
 2-1








RC 83　(RC1302/00） 8,000 2-1 Clockwise

RC 87　(RC 1303/00) ↑ ↑ AntiClockwise

RC 90　(RC1302/01) ↑ ↑ Clockwise

RC 95　(RC 1302/02) ↑ 4-1 ↑

RC 103　(RC 1303/01) 8,000 4-1 AntiClockwise
Douglas, GrFl
RC 109　(RC 1307/00) 10,000 ↑ AntiClockwise

RC 115 8000 ↑ AntiClock + yellow graphics
BlackLightning
RC 120 12,000 ↑ Clockwise

RC 121 9,000 2-1 ↑

RC 126　(RC 1305/00) 8,000 ↑ ↑

RC 127 9,000 4-1 ↑

RC 130 EX9 ↑ ↑ CW, angle drive,Tel Tale

RC 134　(RC 1501/00) 10,000 ↑ Clockwise

RC 145 12,000 ↑ ↑

RC 157 EX1 ↑ 2-1 Clockwise,Tel Tale hand

RC 157 EX2 ↑ 6-1 Clockwise,Tel Tale hand

RC 157 EX4 ↑ 4-1 Clockwise,Tel Tale hand

RC 158 12,000 4-1 Clockwise

RC 166 8,000 2-1 AntiCW,5in,Tel Tale hand

RC 184 8,000 4-1 AntiClockwise

RC 1301/00 ↑ ↑ Clockwise

RC 1301/02 ↑ ↑ CW,Light,Tel Tale hand

RC 1302/00 ↑ 2-1 Clockwise,B.T.T.Flange,Light

RC 1302/03 10,000 4-1 ↑

RC 1302/04 8,000 3-1 ↑

RC 1303/00 ↑ 2-1 ↑

RC 1303/01 8,000 4-1 AntiClockwise, Light

RC 1303/03 ↑ 3-1 ↑

RC 1304/00 ↑ 4-1 Clockwise

RC 1305/00 ↑ 2-1 Clockwise, Light

RC 1307/00 10,000 4-1 AntiClockwise, Light

RC 1307/01 8,000 2-1 AntiClockwise, Light

RC 1307/02 10,000 ↑ AntiClockwise, Light

RC 1309/00 8,000 ↑ Clockwise, Light

RC 1310/02 10,000 ↑ Clockwise

RC 1313/00 ↑ 4-1 Clockwise, Light







Gear Boxes/Revcounter Drives
Part Number Ratio
Input Output Notes
Originally 70549 series was cheap die cast with plain bronze bearings
70549/00
 1-1
Reversing
70549/01
 2-1
Reversing





36362/00
 1-1
Reversing
36362/01
 2-1
Reversing
Originally BG1506 series was a cast substantial bronze body, offering plain bushes for shafts....replaced by 1508
BG 1506/00 1-1
NonReversing
BG 1506/01 2-1
Reversing
BG 1506/02
 1-1
NonReversing
BG 1506/03
 1-1
NonReversing
BG 1506/04 1-1
↑
BG 1506/05
 1-1
Reversing





Originally the BG1507 series was a substantial bronze cast body , offering ball bearings for the shafts
BG 1507/00 2-1
NonReversing
BG 1507/02 2-1
Reversing
BG 1507/03 4-1
↑
BG 1507/06 8-1
↑
BG 1507/07 8-1
NonReversing
Originally the BG1508 series was a cheap die-cast body, offering bronze bushing for the shafts
BG 1508/00 1-1
Reversing
BG 1508/01 2-1
↑
BG 1508/02
 1-1
NonReversing
BG 1508/03
 4-1
Reversing
BG 1508/04 1-1
↑
BG 1508/05 1-1
↑ replaces BG1508/04
BG 1508/06 2-1
↑





BG 2410/00 1-1
NonReversing
BG 2412/00 1-1
Reversing
BG 1530/24



BG 1530/31 2-1
Reversing
BG 1530/104 21-10
↑
BG 1530/106 21-10
↑
BG 1530/111 21-10
↑
BG 5330/164



BG 1530/168 15-12
Reversing
BG 1530/171 15-12
↑
BG 1530/247 2-1
↑
BG 1530/287 2-1
↑
BG 1530/847 19-20
↑
BG 5331/227 2-1
↑
BG 5331/247 2-1
↑





see-
http://velobanjogent.blogspot.com/search/label/Vincent%20speedometer%20information
http://velobanjogent.blogspot.com/search/label/Drive%20gearboxes-%20tachometer%20type
Smiths Auto Tempo Racing Competition Tachometers
Part Number Max. Revs. Ratio Direction Needle Application
ATRC 2652 9,000 4-1 Clockwise

ATRC 2654 12,000 ↑ ↑

ATRC 2654/1 12,000 ↑ AntiClockwise

ATRC 2794 12,000 ↑ Clockwise

ATRC 2794/1 15,000 ↑ AntiClockwise

ATRC 3151 9,000 2-1 Clockwise

ATRC 3541 10,000 ↑ ↑


http://vintagebritishcables.net/index.php

revised March 26,2013 - BG1508 drive descriptions