I find that bike squads are inefficient to use in a combat role. You just pay too many points for each gun once you have taken the price of the bike itself into account.
You can have things like 3 man units with 2 melta guns but I think there are other options that are better for killing vehicles. I'd probably just take land speeders for my fast attack.
To illustrate this, your unit costs slightly more points than 3 land speeder tornados with assault cannons and heavy bolters. I can't really think of any situation where it would be preferable to have the bikes instead of the land speeders. I don't really see the bikes' ability to assault as an advantage, since it means they can be pinned in assault and taken out of the game. Their short range weapons makes that pretty hard to avoid.
You can have things like 3 man units with 2 melta guns but I think there are other options that are better for killing vehicles. I'd probably just take land speeders for my fast attack.
To illustrate this, your unit costs slightly more points than 3 land speeder tornados with assault cannons and heavy bolters. I can't really think of any situation where it would be preferable to have the bikes instead of the land speeders. I don't really see the bikes' ability to assault as an advantage, since it means they can be pinned in assault and taken out of the game. Their short range weapons makes that pretty hard to avoid.