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Theory & Identification

2 Stroke gas engine theorySource: Clymer Manual

2 stroke theory - clymer

2StrokeA little visual of a 2 stroke in action with sound resonation.  (i.e. How 2 strokes create power)

4 Stroke gas engine theorySource: Clymer Manual

4 stroke gas theory - Clymer manual

4 Stroke diesel engine theorySource: Clymer Manual

4 stroke diesel theory - clymer

Model year identification

In 1980, the governement forced motorcycle manufacturers to all use the same sytem of identification, the 17 digit vin.  Before then, it was at the discresion of the manufacturer to label their bikes and each had their own unique numbering system.  Therefore identifying anything before 1980 is nearly impossible.  Now, with the use of 17 digit vins, all one has to do is count to the 10th digit and compare it with the chart below to see what year the vehicle is.

A=1980,  B=1981,  C=1982,  D=1983,  E=1984,  F=1985,  G=1986,  H=1987,  J=1988,  K=1989,  L=1990,  M=1991,  N=1992,  P=1993,  R=1994,  S=1995,  T=1996,  V=1997,  W=1998,  X=1999,  Y=2000,  1=2001,  2=2002,  3=2003,  4=2004,  5=2005,  6=2006,  7=2007,  8=2008,  9=2009,  A=2010,  B=2011,  C=2012,  D=2013,  E=2014,  F=2015,  G=2016,  H=2017,  J=2018,  K=2019,  L=2020,  M=2021,  N=2022,  P=2023,  R=2024,  S=2025

You may notice that I, O, Q, U and Z are not included in the chart.  This is because an I can look like a 1.  O, Q and U can look like a 0 (Zero) and Z can look like a 2.  You will never find these letters as the 10th digit in a vin.  If you think you do, they are numbers not letters.

4 Stroke piston ring identification and installation layout – Source: JE Pistons

Pull chord rope size chart

rope size chart

 Tire Code Decoder – Be sure to check for old tires !

tire code decoder