Z1b oil pan bolts. Washers or not?

my parts book show washers but y pan didn't have any and i don't see and marks on the aluminum pan that suggest that washers were ever used.
Also for 75 the bolts part number changed from 73/74

Yeah, you are correct...Mother Kaw called for 17 6mm washers for the oil pan bolts. Obviously you have gotten by without them but to be safe, I'd use them...torque to specification with the washers and all should be fine.

It depends what kind of bolt you have to whether or not washers were fitted. Early bolts were just a simple hex bolt and used washers, later were the flanged bolt that did not use washers. The same exact flanged bolt was used on most everything from 1976-up and none of them used a washer.

OK, I looked up for a 76 Z900, and it use the same bolts than my 75 but no washers.
So, 73/74 use washers and 75 up whith the new bolts don't.
BTW, great forum.

No washers on my 1979. Just bolts with a very wide faced head.