Need help identifying a bicycle card deck?
I used to play with my cards alot about 2 years ago and did magic tricks etc. I have recently started again so i uncovered a couple of cards including my tally-hos, bees etc. I also found a gaff deck whichi have never used before and would like to know what they are and how to do the trick
They are disguised as a Blue bicycle deck( rider back )
Half of the cards are normal size and have a face and no back design.
The other half are smaller and are blank but show a back design.
Each card is alternating between big and small.
Please help by telling me how to do this trick in your own words or witha link and tell me what they are 
Thanks
A gaff deck is designed for you to take out specific cards from it and add them to a normal deck. So there's not one single magic trick or effect you can do with the deck itself, but you can add them to a regular deck to pull many interesting effects off. Just to give you an example, one of my gaffed cards is mostly blue backed (bicycle deck), but there's a smear of red. So I add it to a regular deck just before i do a color change, so I can make it seem like I'm only doing it halfway, and they can "really see that it's changing" and then complete it.
So basically you're not supposed to do one trick with the whole deck, you're supposed to take them out and work with them individually (or sometimes with small packets of cards from the deck)
EDIT
Now that I think about it, the deck you described might be a form of a svengali deck. The only thing i can think of is you need to riffle one way to show all the cards are blank, and then riffle the other way to show that its a full deck.
Magic trick: uncover the card