Are the '85 250sx/Fourtrax Engine's the same?

[RaceBannon]

I seem to have aquired an '85 Fourtrax 250 (shaft drive). Is this engine the same as the 250sx? If it is I am going to keep it as a spare. Would there be anything else that interchanges?

[dougspcs]

The 250ES, 250SX and 250fourtrax engine/transmission are interchangeable and will work.

However there is minor variation with transmission gear ratios. If my memory is correct and someone will correct me if not, the 250ES & 250 Fourtrax are identical since the Fourtrax is just a 4 wheeled Big Red. The SX has a slightly lower transmision gear ratios due to the smaller tires and lighter machine..more for sport!

Same with the rear differentials.

Also, one of the members here took the rear trailing arm from the Fourtrax (it's a few inches longer) and with some minor mods installed it on his 250SX. If brought the rear axle back about 3-4 inches..

So yeah there are a few things interchangeable from the Fourtrax!