The speed difference between motorcycle and bicycle is minimal in Bangalore. Also there are very little routes where only cycles can go and motorcycles can't. So Google might be doing number crunching with their data for the bicycle routing.
As a workaround you can check if the WALK mode helps for your preferred routes.
In India, bikes are allowed by default on most roads; that is_not something Google India maps seems to take into account. Which seems fair, because there maybe legal / safety aspects they need to consider, if they show roads as being bikable by default.
As the other post said, you could like at "motorbike" routes as an alternative.
I am guessing that something similar might apply to walking routes as well. If some road does_not have a footpath, Google India maps may_not show that road in a wakling route; when we know that you can walk along most roads (that too, legally, AFAIK), in India.
-{db}.