[test-reg]

I don't know when they changed from 41 to43 mm, but a micrometer should solve that question for you. You may also want to change bushings while you are in there.

 

[test-reg]

Opps! I meant to type 40, not 41. If you have Showas they will say Showa on the inside of the lower and will have a 17 mm hex on the cap. Since Brad says your bike came with Marzocchis one can assume if you have Showas they are probably replacements so check the size for sure.