i agree, at first, the FIM class structure can be very confuseing, but once you understand it, no problems,,, there was a link on the old BUB site that gave a comparason between the AMA and FIM classes,, do a search on that site, but, im not sure if its still there,,
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you basically have two "Divisions", naked and streamlining,(streamliners such as Acks are a different division again), there is no production, modified or special construction,, also, in all the Classes (engine cc sizes) there are 1,2,3 and 4 cylinder uuummmm sections, a twin cylinder record is recognized as seperate to a four cylinder,,,
i will use your bike mentioned as an example:- it is propelled by the action of one wheel on the ground, puts it in "Category 1",dose it have two wheels making one track on the ground? yes slots it into "Group A1", dose it have streamlining of any kind?, no will slot it into "Division A", yes will slot it into "Division B", dose it have spark ignition and is naturally aspirated?, no will slot it into "Type 2", yes will slot it into "Type 1", ok its a twin cylinder 1190cc which slots it into "Class 11" (1350cc),,,,
"so if its naked, naturally aspirated and spark ignition:- Category 1, Group A1, Division A, Type 1, Class 11(2)",,,