Ht1kid, not sure what spacer you have but part number is 183-25183-00 is 12mm id x 18mm od x 16mm long.
As soon as you said 12mm long, it didn't sound right to me.
Here's a parts list from a YAS1C which uses the same part and has the dimensions of the part with it.

https://

Hey Pete item 33 #90387-12095-00 according to my listings. I think between me and you he should be good if not we will figure it out  

i.imgur.com/Ilde4Bu.jpeg
  If I need to I can pop the seal out

The Yamaha parts list calls for 183-25183-00. I see the alternative part listed 90387-12095-00 on CMSNL and I see a photograph of it.
Looking at the 18mm diameter it certainly looks about 16mm long.
Htikid, not sure what popping the seal out will show us.
Do you have a photograph of your spacer showing the length?
 

i.imgur.com/H9RlKF3.jpeg

i.imgur.com/O0zguD9.jpeg

#33 collar is pressed into #32 dust cover. Pete I saw my mistake when I pulled the seal out it was the bearing that was measured good catch. 

Glad we've sorted it out, I was starting to question myself and would have probably pulled a front wheel to check. 
Out of interest, is that the '71 parts list from the tech library? I used the '69-'71 parts list as we were looking for the '70 model.

Hey Pete no I copied mine from a local Yamaha dealer here years ago