I took off the stock air filter and measured the throat for a Uni Filter. It measures 2 1/4". From what I'm seeing here, it seems to be the opinion all 1000's have a 2 1/2" throat.
Am I missing something or do you think I have an " earlier " model 2018 ? Any input for a newbie would be greatly appreciated !

[2015 Z Force 800 53/Trail EPS]

I took off the stock air filter and measured the throat for a Uni Filter. It measures 2 1/4". From what I'm seeing here, it seems to be the opinion all 1000's have a 2 1/2" throat.
Am I missing something or do you think I have an " earlier " model 2018 ? Any input for a newbie would be greatly appreciated !

Everyone that have posted said they measured the OD of the adapter sleeve, the tube the filter slides onto,  and because it is metric, the closest fit was 2.5". What did you measure? The parts list shows a different filter over the 800s and a larger TB...and different airbox boot as well.

Maybe one of those fine folks at the factory grabbed an 800's box assembly for yours my mistake.

I took off the stock air filter and measured the throat for a Uni Filter. It measures 2 1/4". From what I'm seeing here, it seems to be the opinion all 1000's have a 2 1/2" throat.
Am I missing something or do you think I have an " earlier " model 2018 ? Any input for a newbie would be greatly appreciated !

I received my ZFORCE 1000 in May 2018, but don't know if it's an "earlier" model or not.  What I do know is the 2 1/4 inch throat air filters recommended for the ZForce 800's don't fit (sent it back) and the ones with a 2 1/2 inch throat do fit.  I have both a Uni Filter UP-6245ST (6 inch long) and a Uni Filter NU-8503ST (8 inch long) and they both fit fine.  I had to reverse (swap ends) on the adapter because of the flange on the stock filter end, and filed off the flange a little bit before I stuck it in the engine side.  I'm new at this too.  Finally figured out that vice grips or channel lock pliers are the easy way to put the clamps back on the air box cover.  Until I figure that out, that was the hardest part of the job.