Alan Sputhe began his association with R & S Pattern Co.: A company specializing in the design and manufacture of patterns, permanent molds and investment dies.  A reputation for quality and innovation led to contracts with NASA to build wind tunnel models for the Space Shuttle; food and pharmaceutical processing equipment; medical and dental instruments.  This diversification led to the formation of Sputhe, a company that integrated engineering with the manufacturing process.


1973 Developed the “mini-sump” for the XR-750 (Harley-Davidson has adopted this feature on every model engine that they build).


Alan Sputhe designed and built a set of dual carburetor aluminum heads for the 1000cc street Sportster that he raced at El Mirage Dry Lake in Southern California.  This machine was timed at 157 m.p.h.


Alan designed and built his first cast aluminum big bore cylinders and redesigned the heads to suit.  The performance of this engine caught the attention of the Harley racers who demanded replicas.
1979 Sputhe began building complete Sportster based 1300cc aluminum XR-750 type engines.


Sputhe powered machines won the AFM Open GP, and Open Super Street Championship and set a record at Bonneville; 1300 MPS-AG at 176 MP (this record still unofficially stands as the 1350 P MPS G record 24 years later), won numerous hill climbs and set many drag strip records.  Cycle World Magazine road tested a street version and declared it to be the “fastest motorcycle of any kind that this magazine has ever tested” (July, 1980).  To this day it is still the fastest Harley-Davidson.


A Sputhe powered machine again won the AFM Open Superstreet and Open GP Championships.  Established a new Bonneville record in 1300 APG-AG.  Alan Sputhe won first place for the 1981 season in S.C.T.A. Dry Lakes Championship.  Moved from Southern California to our present Grass Valley location.
1982 Introduced offset cam chest, high deck, Sportster crankcases
1983 Built the first of the famous 5-speed automatic Sportsters.
 1984  Introduced the 5-speed transmission case for 4-speed frames.  Built the first 4-valve heads for Harley-Davidson Big Twins.  
1985 Acquired Froyd’s Grinding Service, which greatly expanded our production capabilities.
1986 Introduced the 95” and 104” aluminum EVO cylinder kits.  Acquired the Nitralloy Co.  Moved into our present building.
1990 Became totally CNC.  All machine work is now done in-house.  Introduced an improved die-cast version of the Nitralloy ™ cylinders.
1991 The first Sputhe 60-degree installed in a road bike (112 cid. in a FLHT chassis).  60-degree engine banned from US drag racing.
1992 Began production of Big Twin crankcases, high performance EVO cylinder heads, The Sputhe 60-degree engine, and dual carb induction systems.  Australian Danny Grotto sets records on 120 cid. 60-degree Sputhe powered dragster.
1993 Began production of complete 5-speed transmissions for 4-speed frames, high deck 4-inch bore racing and street crankcases.  The first 125” Evo engines.
1996 Began producing high performance Sputhe FXR type motorcycles custom built to the customer’s specifications.
1997 The Sputhe Spectre set an unofficial Bonneville record of 158 m.p.h. (poor salt condition canceled formal record attempts that year) and won the White Brothers Horsepower shootout with 125 hp at the Long Beach Mukuni Show.
1998 Began limited series production of the Spectre motorcycle powered by the Sputhe 60-degree engine.
2002 Introduced right side drive transmissions.  Introduced the Fatvo crankcase.  Introduced a super narrow version of the kick-starter five speeds for four speed frames.  Introduced lightweight aluminum swing arms for FXR, FXD, FXST, – XL and Buell.
2003 Introduced super heavy-duty gear clusters for drag racing and big inch street bikes.  Introduced a totally redesigned 4 to 5 speed case and bearing housing that is twice as strong as any other case made.  Introduced belt drive primaries for Softails.
2004 Introduced the automatic neutral finder and a wide tire kit for Dynas. 
2005 Primary Belt Drive earned Easyrider’s award for Performance Product 2005.


Mike Lodsdens Areal Rectangular 8 1987








Mike Lodsdens Sportster Bonneville 1979