jasenr,Not the resident expert by no means.But here is what I know.The #'s are the engine displacement, rounded off.(my 250 is actually 246cc)The letters are for the different models,i.e. mine is an sx(cross between utility & sport,excellent all around trike). X's are strictly for sport/racing,as were the R's.Yes, es's are big reds,I believe they were made in the 200 & 250 cc models (utility trikes-frt. & rear racks, hi/lo range,elec. start,reverse)Don't know too many specifics about the other models.Maybe someone else can shed a little more light?Hope this helped!!
Al
TF03/HASPIN ACRES /BADLANDS SURVIVOR!!! -LIFE IS GOOD!!
'86 350x (latest addition)
'85 250sx-200x frt.end,350x bars,plastic tank,3"hub spacers,22x11x10 Fast-Trekkers/.190 Douglas Red Label alum. rims/PRM desert grab bar
'85 250sx(supertrap exhaust,chrome rims)
'87 200x(restored)-'85 200x-'84 200x