Great fit on the Z1R, but the lense can be a little tricky to replace. First, open the lens all the way up. Then one side at a time, pull straight forward. All three tabs slide in a groove and release. To replace, reverse the process by placing the lens in the full open position, and slide the tabs straight back in the grooves until you hear it click in.
My helmet size is Large.
I have several of those (open face) large helmets and all fit well from brand new.
I ordered a "Large" Z1R helmet and when it came I found that it was impossible to put it on my head Extremely tight!
I returned it and after a long, long time (wait) I was able to get an "Extra large".
This one was slightly better. I could barely put it around my head, but still quite tight.
I gave up. I got tired returning them and waiting for the next size up.
The helmet itself and padding is good quality, but the sizing is completely unrealistic!
I love the fit of this helmet. It does run large so I ordered what the measurements said I needed and it was too large. I Ordered the next size smaller and it fit perfect. I do wish the visor was larger. The small visor doesn't block any sun.