I've cycled in Kolkata. I've ridden an Enfield Bullet 500 there too. Great fun.
Wow you're brave being on a motorbike. (I'm being honest)
Indian roads can be pretty scary. I once rode pillion on a motorbike in Dehli, never again!
Size rules out there, so a bus doesn't mind trying to squash you.
The chap I was staying with, his son ended up being knocked off his scooter some weeks after and killed by a bus. Really bad
Having said that, the traffic speed in Kolkata is much lower than Dehli, but I'd still be too scared to go on two wheels.