Triumph engine number dating
The model year started in August of the preceding year - or whenever the factory came back to work after the summer break - and ran through July.
For example: ACxxxxx indicates January and a 1969 model year bike. KHxxxxx indicates September and a 1973 model year bike - this bike would have been shipped in September of 1972.
Matchless pre-1958: Directly below saddle on upper frame rail joint. Aermacchi VIN numbers AMC AJS/Matchless from c1935 Engine numbers usually start with the year of production, followed by model designation, and completed with the production number of the motorcycle.
(Source - Wikipedia) Ariel Serial Numbers redhunter.com/ariel/aomcc_BMW Engine & Frame Numbers Post-1969 BMW 650 numbers BMW motorcycle model, year and VIN errors BSA Serial Numbers BSA Numbering System BSA Frame Numbers at NSW BSA Club BSA Frame Numbers BSA at sunnymeadcycles (PDF) Numbers at BSA C15 Serial Numbers uk/c15/c15_serial_DKW DKW Vehicle Identification NZ350 Serial Numbers Frame & Engine Numbers Lambretta Maico Numbers at Maico Madness (See also Sears Allstate)Puch moped chassis numbers Includes links to pages covering MS, MV, VS, VZ, SR, SRA and RL Sachs See also under Penton Sachs 98ccm Modell 1932 Royal Enfield Royal Enfield Serial Numbers at Bikelinks Triumph Triumph Serial Numbers at Bikelinks Triumph Engine & Frame Numbers 1950-1988 at Triumph Serial Numbers at British Triumph 3HW identification Triumph frame & engine numbers 1934-1953 Velocettte Velocette LE Engine & Frame Numbers Velosolex Velosolex engine serial numbers Vespa Identification garnersclassicscooters.com/scooterhelp.com/serial/serial.This page includes information on Vespas made under licence by Douglas, ACMA in France, and Motovespa in Spain, along with those marketed in the United States by Sears under the Allstate marque.
The best source of this data is , by Lindsay Brooke and David Gaylin.
Most of the models with question marks after dates are identified in their book for US entry.
On some models the model identifier appears at the beginning and on other models the model identifier appears at the end. By far the most common location is on the steering head.Motobecane Mobylette 1968: Forward of the rear wheel axle on left side. James Rigid frames: usually stamped on the lug beneath the saddle on LHSPlunger frames: saddle lug (same as rigid), or on the steering head, LHSSwing arm frames: stamped into steering head and/or into a steel ID plate pop-rivetted onto the steering head.The date code always appears immediately preceding the five digit, sequential serial number.Frame and Engine numbers would have matched when the bike left the factory.