240 vs 250

I have always wondered:

In regards to the 1983/1984 Husky bikes (and possibly other years):

Why were the motorcycles in Europe (also Australia?) identified as "240 cc", and the bikes in the US (also Canada?) identified as "250 cc"?

Do the engines actually have a different displacement/size, or was it some sort of government/motor vehicle requirement?

I think the 430 cc bikes are the same, no?

In France some years ago, a 240+ would pay 33% VAT.
A 240 - would pay 19.6% VAT.
So the 240 are 238 cm3 and in others countries the 250 are 240 + to 250.

we have had this before..FIM determined that 250 was Maximum engine size in 82 for 83 and there was no allowance for oversize... thus husky dropped10cc to ensure that with max overbore it was still under 250 ...that's what I was told when I purchased a 240 in 84

Michel is right it's a tax base

right...makes more sense. fim story to convince "must have the biggest engine" customers...how big a market was france to have a whole range of different engines??

WAIT..no issues for oZ why did we get the tiddlers I wonder?? more road going stuff than the US im guessing