The detailed BOM (bill-of-materials) starts here:Top-level BOM

The table below is a very rough overview. As the detailed sections get completed, there will be links added to the table below.

Year	1952 K	1953 K	1954 K	1955 K	1956 K	1957 XL	1958 XL	1959 XL	1960 XL	1961 XL	1962 XL	1963 XL	1964 XL	1965 XL	1966 XL	1967 XL	1968 XL	1969 XL	1970 XL	1971 XL	1972 XL	1973 XL	1974 XL	1975 XL	1976 XL	1977 XL	1978 XL	1977 XLCR	1979 XL	1980 XL	1981 XL	1982 XL	1983 XL	1984 XL	1983/4 XR-1000	Year
Engine	740cc 45cid flat head no trap door		900cc 55cid flat head			900cc 55cid OHV										900cc 55cid OHV elect start					.1000cc 61CID		Speedo drive removed from transmission			All-new case, no timed breather, different oil pump, different sprocket and pinion bearing and flywheels to match					No kickstarter planetary electric start				like 81-84 but alum heads, cylinder studs	Engine
Engine XLCH	NA					Same case, 900cc 55cid OHV													Same case, no elect		.1000cc 61CID		Speedo drive removed from transmission								No kickstarter planetary electric start				like 81-84 but alum heads, cylinder studs	Engine XLCH
Front Brake	Side drum												Hub drum									Bana disk	single disk				Dual disk rattler							modern single disk		Front brake
Rear Brake	Drum rod																						Drum cable					Disk rattler				Disk modern				Rear brake
Shifter	Right side																						Left side kludge			Left side										Shifter
Frame	Cast joints, no dent in under side of top tube					Cast joints, dent in under side of top tube										Cast joints, dent in under side of top tube, angled rear tubes							Welded joints, dent in under side of top tube, angled rear tubes					Triangle				Modern loop				Frame
Gear case	Mount distrib and magneto																			Cone, old pinion shaft						Cone, new pinion shaft										Gear case
Primary	Single rib aluminum					Sportster logo XLH, Tin XLCH 1958-1969										Hump aluminum (other than 67-69 XLCH)										Hump aluminum new case										Primary
Gen	6-volt													12V Prestolite																		12-volt Hitachi				Gen
Starter	NA															Prestolite							Hitachi			Back to Prestolite					Nippon denso planetary					Starter
Gas XLH	Large flat- bottom					Large dented bottom				Turtle																Peanut		CR tank	Peanut new mount			Peanut yet a new mount	Peanut, yet a different mount			Gas Tank
Gas XLCH	NA							Peanut																				CR tank	NA	XLS:Large maybe gage		XLS: rubber mount	XLS: Dash		NA	Gas XLCH
Front fender	Struts, rear flair				Struts, no flair			Valenced								Struts, no flair			Top mount, braces; 1983 XLXTop mount one off 59031 -83															Top mount 59007-84		Front fender
Front fender XLCH	NA						Struts, no flair												Top mount, braces; 1983 XLXTop mount one off 59031 -83															Top mount 59007-84		Front fender XLCH
Year	1952 K	1953 K	1954 K	1955 K	1956 K	1957 XL	1958 XL	1959 XL	1960 XL	1961 XL	1962 XL	1963 XL	1964 XL	1965 XL	1966 XL	1967 XL	1968 XL	1969 XL	1970 XL	1971 XL	1972 XL	1973 XL	1974 XL	1975 XL	1976 XL	1977 XL	1978 XL	1977 XLCR	1979 XL	1980 XL	1981 XL	1982 XL	1983 XL	1984 XL	1983/4 XR-1000	Year
Oil tank K, XLH	Kidney																											Triangle				Loop				Oil tank K, XLH
oil tank XLCH	NA							Horse shoe						Lunch box														Triangle				Loop				oil tank
Battery	6V													Two 6V		12V H12 28AH 28AH												YB16-B fact 65991 -75C				YB16-B fact 65991- 82A				Battery
Battery XLCH	none																		12V 7AH									YB16-B fact 65991 -75C				YB16-B fact 65991- 82A				Battery XLCH
Tail lamp	Hood				Hole in fender, two lenses																	One piece lens														Tail lamp
Rear shocks	Early															middle								Showa				12.7 13.5 opt		12.5		late				Rear shocks
Exhaust	Single, separate front and rear pipes					Single comb front and rear pipes	Inter connected duals, short mufflers, high pupe XLCH 1959				Staggered duals, many others fit or were optional									integrated qiet		Staggered duals		Staggered dual with crossover		Single muffler		Dual both sides will fit 54-78		staggered duals new mount					left side	Exhaust
Head lamp	Bottom mount							Eye brow XLCH, New bot mount XLH with nacelle											Eye brow																	Head lamp
Clutch	Dry																			Wet, 1980 and later has diff ring gear																Clutch
Kick starter	Yes																													No						Kick starter
Carb	Linkert					L-carb									Tillotson						Bendix					Keihin butterfly									del orto dual	Carb
Front end	Cow bell		Gator, axle fender mount																Top mount fender			Kaya	Showa single disk				Showa dual disk							Modern single disk		Front end
Trans mission	4-spped crash box																																			Trans mission
Year	1952 K	1953 K	1954 K	1955 K	1956 K	1957 XL	1958 XL	1959 XL	1960 XL	1961 XL	1962 XL	1963 XL	1964 XL	1965 XL	1966 XL	1967 XL	1968 XL	1969 XL	1970 XL	1971 XL	1972 XL	1973 XL	1974 XL	1975 XL	1976 XL	1977 XL	1978 XL	1977 XLCR	1979 XL	1980 XL	1981 XL	1982 XL	1983 XL	1984 XL	1983 XR-1000	Year

What this BOM is about:

This BOM section attempts to document the exact part numbers used in Iron Sportsters and K-models made between 1952 and 1984. While the late 1984 is an Iron Sportster, the alternator buried behind the clutch is too different to be included in this site.
This listing tries to be precise and exact, relying on the Harley parts books combined with detective work by folks like the HarleyKmodel site. Note the 1977 XLCR is moved next to the 1979 models to simplify the chart. The 1983 XR-1000 is combined with the 1984 XR-1000 column for the same reason.
This detailed BOM is built by the web CMS (content management software). When I add a component, it automatically shows up in the assemblies it belongs to.
The BOM is very incomplete. It takes an immense amount of time pouring through parts books, and even then, there can be confusions and mistakes.
You can use the BOM to find the parts that are supposed to be on your bike. Since many Sportster parts fit other years, this can help you detect what assemblies you bike uses, and the part numbers you need to find to repair, restore, or customize it.
Keep checking back, as there is now a major effort to at least fill in the major assemblies. If one of the component names in the table above becomes a link, that means that part has been figured out and put in the detailed BOM.
Comment at the harleyKmodel site.

The detailed BOM (bill-of-materials) starts here:Top-level BOM

What this BOM is about:

The sub-assemblies at the right can help you navigate to what parts you are interested in.

Sub-assemblies