there must be some type of restriction otherwise everyone would be doing the samething! please advice.
Most of the processes for depositing funds into exchanges have fees associated.
Then most exchanges charge an exchange fee for performing the exchange.
Then you'll pay another exchange fee for performing the exchange again on the other exchange.
Then most of the processes for withdrawing funds from an exchange have fees associated as well.
By the time you've paid all the fees, you may not have as much profit as you thought.
Additionally, Are you sure that you are comparing the "bid" price at one exchange with the "ask" price of the other?
When purchasing bitcoins at an exchange, you'll pay the "ask" price (assuming there is no slippage, otherwise you'll pay a bit more than the "ask" price).
When selling bitcoins at the other exchange, you'll only receive the "bid" price (assuming there is no slippage, otherwise you'll receive a bit less than the "bid" price).
If you are comparing "spot" price (or "current" price), then you may be comparing them backwards.
