Maybe you all knew this, but I just figured it out today.
There is an obvious difference in two styles of RH side panels.
One style was flatter across the number plate area, and the other was bi-level with a step down toward the front edge.
I have 4 original side panels, all from 1974 models.
The two green ones are from MX models, and the two yellow ones, are off of Enduro models.
(http://i52.photobucket.com/albums/g8/BobWardlow/PARTS/11JAN011_zps4722d887.jpg)
Makes sense, duh. The ones with the step (yellow), stick out further and are made as clearance for bigger / fatter enduro pipes.
(http://i52.photobucket.com/albums/g8/BobWardlow/PARTS/11JAN017_zps6df47fa0.jpg)
You can also see in the picture above, they altered the profile on the MX models, where the arrow shows, it's tucked in more for smaller MX pipes.
I learn something everyday.
Bob
Front to back - the yellow enduro panels are also shorter than the green MX panels.
(http://i52.photobucket.com/albums/g8/BobWardlow/PARTS/11JAN028_zps76ced507.jpg)
Bob,
I think it is actually because of the late 74.5 laid down shock clearance, but the left side metal panel used at first on those 74.5 laid down shock versions are bent out for clearance, then later on they went to the plastic one with the cut out area of the numberplate for the clearance issue. I have had all 3 styles on the chassis change models of 250's, early 74, late 74-75 and 76. Plus the RH exhaust panel side has a bigger curvature for the 250/400 pipe than the 125/175 panel. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R