Indian Motorcycle Serial Numbers Unraveled

J	A	B	C	D	E	F	G	H	I
0	1	2	3	4	5	6	7	8	9

Frame
Arrow	1xx
Scout/Warrior/TT	2xx
Chief	3xx

1950 -1953 Top
Midstream the 1950 Chief serial numbers changed from CEJ to just C on BOTH engines and frames, upsetting the rules as shown in the 1932-1950 table below . Early 50's Chiefs were CEJ, late '50 and' 51 Chiefs were just 'C', and all '52 and '53 Chiefs were 'CS' . When this change happened all vertical twins also had frame numbers matching the engine exactly too. Examples :
Eng# BEJ911, Frame # 250911 is 1950 Warrior.
Eng# B1003, Frame # B1003 is 1951 Warrior. Top

	A	B	C	D	E	F	G	H	I
0	1	2	3	4	5	6	7	8	9

Frame
Jr. Scout	5xx
Std Scout, & VT	2xx
Sport Scout, MP	6xx
101 Scout	101
741 (mil)	741
841 (mil)	841
Chief	3xx
Indian 4	4xx

MP=Motoplane (in Jr.Scout frame)
VT=Vertical Twins excl Arrow.

1932 -1950 Frame Numbers introduced late 1930 early 1931 (see note 9) Top
Example: we have an unknown motor (or cycle) that's stamped CDF 6403 and a spare frame stamped 441 1089 <work in reverse, i.e. numerals to letters using table or your fingers!>

1st letter is C, this is the series,
all Chiefs are 3, Fours are 4 etc (see table left)
2nd letter D is the decade year 4 and the
3rd letter F is the digit year 6

Answers:
Motor is 1946 Chief, Serial# 6403 (6303rd* made!)
Frame is 1941 Four, Serial# 1089, (989th* made!) *as first machine started at xxx101

In order for a cycle to have 'matching numbers', the frame number must match the engine number and the first three numeric digits of the frame number equal the decoded motor number. i.e. for our example, the frame would have to read 346 6403. see Frame Numbers section Top

	A	B	C	D	E	F
Yr	'26	'27	'28	'29	'30	'31

Engine
Prince 21ci	L
Scout 37ci	G
Scout 45ci	GP
Chief 61ci	Z
Big Chief 74ci	H
Four 1926/7	E
Four 1928-1931	A

1926 -1931 Top
Indian lost the plot for a few years between 1925 and 1933 with their numbering, possibly exacerbated by the 101 series 'no new model years', the Ace acquisition and how to incorporate frame numbers in 1930/31 which I will ignore in this scenario.

Examples:
AH1088 is a 1926 Big Chief, 74ci, serial 1088
(similarly, AZ1088 would be 1926 61ci)
BGP1055 is a 1927 Scout, 45ci, serial 1055
(similarly, BG1055 would be 1927 Scout 37ci)
EA779 is a 1930 Four, serial 779
(similarly, BL779 would be 1926 Prince) Top

Model/hp (Hendee/Indian)
1= 2�hp single
2 = 5hp twin or 2�hp single
3 = 4hp twin or 2�hp twin,
or 21ci Prince single
4 = 4hp single or 30.5ci Pplus
5 = 7hp twin or Scout 37"
7 = 7hp twin or 61ci PowerPlus
8 = 8hp twin or Chief 61ci
9 = Chief 74ci or 72ci Powerplus

Years Example
A=1909
B=1910
C=1911
D=1912
E=1913 Ex.3
F=1914
G=1915
H=1916
J=1917
K=1918
M=1919 Ex.2
R=1920
S=1921
T=1922
V=1923
X=1924 Ex.1
Y=1925

(I, L, N-Q, U & W not used.)
also see note 12 for ?Pxxx models (where ?=R,S,T or V)

1909 -1925 hang on it gets a little tougher now!. Top
Its a little like an odometer that clocks over in units, tens, hundreds and thousands and tens of thousands. You may find it easier to pay attention to the year first, then look at table and determine the models for that year, see Example 2.

Example 1 - 51X107
Take the engine number 51X107 which breaks down to:
5 is Scout 37", (because of X) then because the second number is not zero (as it would be if serial < 1000) we add it (1000) to the serial 107 making it 1,107,
The X is the year 1924. So it is a 1924 Scout with a engine serial of 1107...
eg. a serial of 54X155 would be the same model and yr with a serial of 4,155.
similarly, a serial of 67X157 would be the same model and yr with a serial of 17,157.

Example 2 - 72M911
Take the engine number 72M911 which breaks down to:
'72 equals 7 &2 and think of this as 2000 (thousandths digit)
The M is the year 1919. The 7 is a 61ci Powerplus (because of the M) and the remaining 2000 is the thousandths unit of the engine number whereby adding it to 911 gives us 2,911.
So it is a 1919 Indian Powerplus with a engine serial of 2911...

similarly, a serial of 81M177 would be the same model and yr with a serial of 11177.

Example 3 - 86E630 <please see note 8>
Take the engine number 86E630 which breaks down to:
86 equals 7 &10+6, think of this as 10000 (ten thousandths digit, i.e 70xxx-80xxx), then add this PLUS the 6000 (thousandths) to the 630 it gives us16,630.
The E is the year 1913. The 7 is a 7hp Hendee twin. So it is a 1913 7hp Twin with a engine serial of 16630...

similarly, a serial of 70E433 would be the same model and yr with a serial of 433. Top

1902 101-243
1903 244-620
1904 621-1167
1905 1168-2349
1906 2350-4048

1902 -1908 Top
There was no commercial sales in 1901 but numbering began 1902 starting at #101 and remaining in sequence to #4048 until 1906. This gives us an insight into production numbers. From this point till 1909 as the database illustrates, its anyone's guess what someone was dreaming up! Top

Engine number suffixes Top
"A letter may be stamped after the engine number (but off to right of boss itself, i.e. on crankcase): these letters are:-
A is for aluminum pistons which were optional over std cast iron pistons in scout 45"in 1928 see note 5
B is for Battery ignition (distributor). (post 1933, see below note) ...BUT
   B was also used (briefly) to denote blackout lighting fitted by the factory on mil. cycles during WWII. see note 6
   B also designated aluminum piston and/or special clearances for performance and/or sustained speeds on pre '28".
   B also designated aluminum piston, chief carb (DLX81?), chief valve springs and chief inlet nipples/manifold used on
special factory 101 Scouts.
BM is for Bonneville Motor.
BY is for Battery (Distributor) ignition on 'Y' motors, i.e.. Y manifolds, trench heads (Ricardo) etc - mostly mid 30's models.
M is for Magneto ignition.
MY is for Magneto ignition on 'Y' motors, - rare, mostly mid thirties models.

Frame number locations (also see note 9) Top
'31 and up rigid frames are on a boss just below the left ear axle slot,
'40 spring frames are on the left rear shock casting above the axle slot,
'41 through '51 are on the lower left shock mounting ring,
'52 through '53 are on the front face of the right front footboard casting mount. thanks to John Welch
'49-'52 VT's (=Vertical Twins), i.e Scouts, Warriors/ TT's and Arrows, have the frame serial on the front forks.
'34-'42 DT's (=Dispatch Tows), i.e 3 wheel Sports Scouts have the frame # under the seat on the frame casting.

Matching Numbers
"The practice of re-stamping frames to match engines to make a 'matching number machine ' an vice versa often results in the frame number being exactly the same as the engine number, eg CDF 4321 and CDF 4321. In actual fact the frame would have been stamped, in this case, 346 4321. This is often the single most giveaway as Indian did not match serials on chiefs till mid 1950, watch out for this on ebay!"

Production Numbers <UNDER CONSTRUCTION>
Much of this data has been gleamed from Jerry Hatfield - but we still need more info please.
key to notes
sc=sidecars, nr=no records?, co=chiefs only, ap=approximate

Year	Qty	Note	Year	Qty	Note	Year	Qty	Note
1901	3		1919	21,500		1937	6,037
1902	143		1920	?	nr	1938	3,650
1903	376		1921	?	nr	1939	3,012
1904	596		1922	?	nr	1940	10,431
1905	1,181		1923	?	nr	1941	8,739
1906	1,698		1924	?	nr	1942	16,647
1907	2,176		1925	?	nr	1943	16,456
1908	3,257		1926	?	nr	1944	17,006
1909	4,771		1927	?	nr	1945	2,070
1910	6,137		1928	?	nr	1946	3,621
1911	9,763		1929	?	nr	1947	11,849
1912	19,500		1930	?	nr	1948-49	9,000	ap
1913	32,000		1931	4,557		1949	?	nr
1914	25,000		1932	2,360		1950	2000+	co,ap
1915	21,000	sc=3,200	1933	1,667		1951	500+	co,ap
1916	22,000	sc=3,700	1934	2,809		1952	500+

Indian Motorcycle Serial Numbers & Model Data 1901-1953