Suzuki RM125 swingarm measurements, more or less (in inches, +/- 1/8)
 as measured by me with a carpenters framing T-square, so take it for 
 what it's worth :)

 All swingarm measurements center-to-center (ie. center of swingarm pivot
 bolt to center of shock mount bolt).

   A - swingarm pivot to shock mount
   B - swingarm pivot to minimum axle position
   C - swingarm pivot to maximum axle position
   D - shock length (unloaded with springs installed)
   E - nominal wheelbase (source: http://www.suzukicycles.org)

              +--------+--------+--------+-----------+------+
              |   A    |   B    |   C    |   D       |  E   |
 +------------+--------+--------+--------+-----------+------+
 |  RM125A    | 12 5/8 | 19 5/8 | 20 5/8 | 14 3/4[4] | 54.9 |
 +------------+--------+--------+--------+-----------+------+
 |  RM125B    | 13     | 20     | 21     | 14 3/4[4] | 55.3 |
 +------------+--------+--------+--------+-----------+------+
 |  RM125C[1] | 13     | 20     | 21     | 14 3/4[4] | 55.3 |
 +------------+--------+--------+--------+-----------+------+
 |  Thor[2]   | 13 3/8 | 19 1/2 | 21     | 14 3/4[4] | ---- |
 +------------+--------+--------+--------+-----------+------+
 |  RM125N[3] | 13     | 20 3/8 | 21 5/8 | 15 1/4[5] | 56.7 |
 +------------+--------+--------+--------+-----------+------+
 |  RM125T[3] | tbd    | tbd    | tbd    | tbd       | 56.7 |
 +------------+--------+--------+--------+-----------+------+

   [1] - The stock RM125C aluminum swingarm is listed as an optional
         component for the RM125B (ie. same part numbers)
         (source: http://www.bikebandit.com).

   [2] - The Thor swingarm I measured is numbered '286S' and is for
         the stock length shocks. I found it on an 'A' frame with
         what I believe to be 'N' shocks.

   [3] - RM125N and RM125T have different swingarm part numbers
         (source: http://www.bikebandit.com); but have the same
         wheelbase (source: http://www.suzukicycles.org).

   [4] - Shock length per 1978 Moto-X Fox catalog and measured with
         carpenters framing square.

   [5] - Shock length as measured by me with carpenters framing square.