HarleyHelp.com - engine comparison

Complete Harley-Davidson motorcycles were manufactured in Milwaukee, Wisconsin, from 1903 through 1972, generally one motor - one assembler, one bike - one assembler. From 1972 through 1997 Harley-Davidson motors have been built in Milwaukee, then shipped to the York, Pennsylvania, plant where the balance of motorcycle components are manufactured and where final assembly takes place on an assembly line. 1997 to the present, most Big Twins are assembled in York and some Big Twin and all Sportster assembly takes place in Kansas City.

Motor ->	Knucklehead	Panhead	Shovelhead	Evolution	Twin Cam 88
Years	1936 to 1947	1948 to 1965*	1966 to 1985	1984 to 1999	1999 to 2006
Recognition
Models	1936 - 1952 ---61” OHV EL 1937 - 1942 ---80” UL 1937 - 1951 ---45” WL 1941 - 1947 ---74” FL 1942 - 1945 ---45” WLA Army, XA 750cc Army	>1948 ---------74” FL Pan 1949 - 1957 74” Hydra Glide 1952 ---------45” K 1954 ---------55” KH 1957 - 1971 55” XL Sportster 1958 - 1963 FL Duo Glide 1965 - 1970 FL Electra Glide	1970 - 1971 - XR750 (1972-80 = Aluminum, 1981- ? engines only) 1971 - 1980 - FLH1200 1971 - 1972 - FX1200 Super Glide 1972 - 1976 - XLH, XLCH 1000cc 1972 --------- Sportster 1974 - 1980 - FXE 1200 1977 -----------FLHS 1977 - 1979 - XLT 1977 - 1978 - XLCR, FXS Low Rider 1978 ----------FLH80 1979 ----------FLH80 Classic, FXS 80, FXEF1200, Fat Bob 1980 ----------FXWG Wide Glide 1980 - 1982 - FLT Tour Glide, FLHS, XLS, FXEF80, FXB Sturgis 1981 - 1986 - FLT Classic 1982 - 1985 - XLS Roadster 1982 ----------XLHA, XLSA 1982 - 1983 -FXR, FXRS Super Glide II, FXSB Belt, FXRT Tour Glide (shovels) 1983 ----------FXDG Disc Glide 1983 - on-----FLHT, FLHTC	1984 - FXST 1984 - FXRDG – only year 1986 - FXR – re-introduced, FLST Heritage Softail 1987 - FXLR Low Rider Custom 1988 - FXSTS Springer Softail 1990 - FLSTF Fat Boy 1991 - FXDB Dyna Glide Sturgis 1992 - FXDB Daytona Dyna Glide – only year 1992 - FXDC Super Glide Dyna Custom 1993 - FXDWG Dyna Wide Glide, FXDL Dyna Low Rider 1995 - FXSTSB Bad Boy, FLHR Road King	In its first year, the Twin Cam 88 is on all the Touring and Dyna models, with the Softails following in 2000.
Displacement	1936 Series E Displacement 1000cc (61ci) Bore 3 5/16 inch Stroke 3 1/2 inch 1941 Series F Displacement 1200cc (74ci) Bore 3 7/16 inch Stroke 3 31/32 inch	E Series Displacement 1000cc (61ci) F Series Displacement 1200cc (74ci)	XL (Sportster) Displacement 900 cc, 1000cc (1972) Big Twin 1200cc (74ci) 1340cc (80ci) (late 1978)	XL (Sportster) Displacement 1100cc (1986), 1200cc (1988). 883cc (1989) Big Twin Displacement: 80 ci Bore: 3.498 inch Stroke: 4.250 inch	Displacement: 1450cc (88ci) Bore: 3.75 inch Stroke: 4.00 inch w/ 1550cc (95ci) Available upgrade
Compression	Available in Low, Medium and High	Available in Low, Medium and High	Available in Low, Medium and High	Compression Ratio: 8.5:1 (BT)	Compression Ratio: 9.0:1
Head Design	Whereas the flat head engine had the intake and exhaust valves on opposite sides of the combustion chamber the valves in the knucklehead were moved to the top of the combustion chambers.	The Panhead didn't change much from the knuckle in internals. But it came equipped with aluminum heads, Valve oilers and noise suppressors.	Larger aluminum version of the Sportster head, with the same hemispherical combustion chamber and valve angle, The true "Hemi" Engine.	New aluminum heads designed to decrease oil leakage while utilizing side-squish combustion chambers and flat pistons	Aluminum permanent mold with 85cc bathtub combustion chamber
Cylinder Design	Cast Iron	Cast Iron with built-in fire ring on top of cylinder	Cast Iron with built-in fire ring on top of cylinder	Aluminum cylinders with pass-through head bolts	50% more fin area for better cooling. Constructed of aluminum high-pressure die cast with cast in Spiney-Lok cast iron liner.
Case Design	Introduced in 37 the recirculating dry sump oiling system. Later models included centrifugal bypass oil pump.	Revised crankcases and cylinders feed oil internally to the heads and return internally to the cases. In 1955 Harley modified the pans by installing a quieter more efficient lower end. In 65 they were the first HD's to have electric start.	Cone style cam cover in 1970 with alternator to replace the generator Later introduction of rubber mounted engine	A new lower end designed for more efficient oiling	Twin gearotor, dry sump, internal oil pump based on the Sportster. Now uses an O ring instead of paper gasket on the base to cylinder. Stronger crankcase mounts. Counterbalanced crank to reduce the classic vibration. (TC88B)
Carburetion	Linkert carburetor on later models	M-74B 1 1/2-inch Linkert carburetor on 74 ci	Tillotson, Bendix, Keihin butterfly carb	Keihin CV, EFI was introduced in 95	Keihin CV or EFI
Transmission	61ci E models had separate 4sp trans constant mesh. Optional three-speed and three-speed-with-reverse transmissions with sliding-gear first on early models. All later Models were 4sp with optional side car gearing.	Both E and F series were available with either hand or foot shifted 4sp transmissions	4sp ratchet top, 4sp plate top, Late introduction of 5sp trans in a 4sp case on FLT model.	By 1991 all models featured the 5sp drum shifter transmission	New shift mechanism that delivers low-effort, quieter gear changes Close ratio gearing
Misc.	The knucklehead motor was the first of the overhead valve motors and succeeded the side-valve flathead (although the latter continued in production throughout the knucklehead era and beyond).	Basically the knucklehead lower end with a new top end with hydraulic valve lifters and aluminum cylinder heads FLH motors are fitted with Victory camshaft that has a higher lift	AMF moved production to an assembly line process dropping quality and increasing production flooding the market with motorcycles that wouldn't sell	To this point the Evo was the most radical departure in engine design for HD In 1992 belt drives were standard on all models.	Twin cams with chain driven spring loaded tensioners Now the Twin Cam has surpassed the Evo in a departure from the design norm. Supposedly only 21 parts are common to the Evo, however, a press release states that fewer 18 parts are shared between the engines
Notes	* Main production models, does not include specialty models such as WL etc. The knuckle received it's nick name by the appearance of the heads which look similar to the knuckles of a fist.	*Panheads had the longest production run of any Harley motor to date, lasting 17 years. The first Sportsters, introduced in 1957, were panheads. See the notes on Shovelheads as to why the shovel was not considered the longest production run. Received it's nick name due to its valve covers look of an upside down cake pan.	*There were two versions of the shovel: the generator or flatside shovel, and the cone motor shovel. The flatside shovel, was produced from 1966 to 1969. A generator was mounted ahead of the front cylinder, giving the motor a relatively flat look. Generator shovels are mistakenly referred to as "pan/shovels," because the the lower end is the same as a panhead.	*The Evolution was referred to as the "Blockhead" for a time but most just called it the "Evo" (pronounced ee-voe)	*The Twin Cam is referred to as the TC88 or the "Fathead" in some circles.