Dura Ace Cranks, fucked?

Shimano BB's are JIS right?

My understanding was that even though Dura Ace is Shimano and therefore the logical assumption would be that they too would be JIS but...

..I went through a similiar thing last week, my Campy BB is ISO and my old cranks were JIS so no go.

When I explained this at 14 they said that both the Campy Record and Dura Ace would be fine as they were track specific and therefore ISO.

My cranks are DA **road **cranks which i run with a single ring.
They have the jis logo stamped on the back.
My understanding was that the road and track cranks were different tapers.
Ergo, DA track cranks will be iso.
Don't know what this means for bmx cranks though, if Shimano even produced DA bmx parts.

However, in the pic of the 2 cranks side by side i'm pretty sure i can see a shelf on the inside of the spider. This to me suggests these are road cranks as the shelf is there to help locate and support an inner chainring and is not present on DA - or really any - track cranks - and presumably would not be present on single chainring use bmx cranks (if they exist) either.

Just because the crank has at some point been fitted to a bmx it does not mean its a genuine bmx part.