Check this out

[Rocket]

Check this item on Ebay, 170574101622, and take a look at the frame.  It has a June of 75 build date and it is not a frame breather.  How many bikes were like this one?
Rocket

[Roy Smithson]

Here is a link.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&_rdc=1&item=170574101622&ru=http%3A%2F%2Fshop.ebay.com%3A80%2F%3F_from%3DR40%26_trksid%3Dp3984.m570.l1313%26_nkw%3D170574101622%26_sacat%3DSee-All-Categories%26_fvi%3D1&viewitem=

[dirtbike]

http://www.pentonusa.org/forum/topic.asp?TOPIC_ID=11801