This cannot be over stated. Indian traffic conditions are chaotic, the drivers reckless, and the roads often in poor repair. There is a pecking order for right of way :cows are at the top, trucks and buses are second, and dogs and pedestrians are at the bottom. Two wheelers are pretty low down. You can only really lord it over bicycles and chickens.
You will not believe the crazy things other drivers are capable of until you've driven here. People overtake on blind corners. They swerve blindly in traffic. They come off side roads at full speed and join the traffic flow without even looking. They stop on a whim in the middle of the road. They barrel down the middle of a narrow road playing chicken - forcing anyone smaller off on the shoulder. Expect anything, at any time. Nor will you believe road conditions.
Pot holes and speed breaker bumps are common, and rarely marked. Rocks are commonly left on the road by a truck that has blocked its wheels while stopped to repair a tire. Pedestrians, animals, bicycles, ox carts and tractors all use the roads.
Sometimes people lie down and have a nap on the edge of the road. Traffic barriers and road dividers appear suddenly and inexplicably. Road repair crews leave piles of sand, gravel, or tar on the road. During harvest times, people spread grain and other crops on the road to dry. You'll suddenly find yourself fishtailing through a 6 inch deep mound of millet seeds. Expect anything, at any time.
Driving in big cities is, initially, a terrifying prospect. So much traffic, so much noise and pollution, and so much chaos. Don't dismay. Driving in large cities is a bit like juggling chainsaws - once you get the rhythm of it you're half way there, but one small slip can be very messy.
The rhythm is the key. Ease into city driving if you can. Concentrate most on what is in front of you. It seems an unwritten rule of the road that people behind you will adjust to what you are doing. Most of the drivers in front of you will assume you are watching out for them. They may pull out suddenly, swerve abruptly, or just stop because they've arrived. Do not assume lanes have any significance. Do not assume lights will be followed either.
Buses are a hazard. They will suddenly swerve to the edge to drop passengers, and pull out abruptly. If they merely slow down at any point, some passengers may decide to jump off, other to jump on. Watch out for carts and rickshaws. Some carry over-sized loads or extra long loads that jut dangerously into traffic. Autoricksaws are constantly in a hurry and zip recklessly through dense traffic. Pedestrians can appear anywhere, at any time. So, of course, can cows, pigs, dogs and other animals.
Here is where you can enjoy the open roads and dramatic country-side, but it is not without its hazards. Your fellow drivers will probably drive very fast, and often quite recklessly. Long haul lorries and buses are usually the worst offenders, and have the unofficial right-of-way due to their size.
Drivers on country roads favour the middle of the road and swerve to their side only at the last minute, often indulging in blood-chilling games of chicken with on-coming traffic. Don't try and play. Slow down and ride the shoulder.
Check your mirrors frequently. Over the sound of your bike you will not hear a vehicle overtaking you. This is particularly necessary before you overtake anyone, even a slow moving oxcart, or when a speeding vehicle is bearing down on you. If there is another truck coming right behind you you will be the loser if the three of you try and pass abreast.
Try and avoid major roads, especially the national highways. Though slightly wider and better maintained, these roads are clogged with speeding trucks, buses and cars. Where possible, take the minor routes. The pace is slower, the scenery is better, and the trip more pleasant.
Use your Headlights
Having headlights on in the daytime is a standard safety requirement in many countries for both cars and bikes. It increases visibility of vehicles in motion and saves lives. Unfortunately, in India, when you drive in daylight with your headlights on you create astonishing stress in the lives of all who see you. Oncoming drivers will flash their lights, other two-wheelers will pull along side trying to tell you your lights are on, and almost every pedestrian you pass will point, wave, and flash their fingers at you. It is annoying as hell, but people here seem to have some kind of primal need to tell you you're lights are on. Try and ignore them. On a road trip I drive with headlights on (except in cities and towns, where the hassle is too much). It makes a difference. At least all those people trying to get your attention have seen you. I've had on-coming trucks start to pull into my lane and then pull back because my headlight was on. I think I was benefiting from the unwritten rule that the driver that first flashes their lights has the right of way.
Don't Drive at night
Road conditions become almost unbearable at night. You face on-coming traffic with astonishingly bright headlights. Few will dim them, and many will flash you just as they pass. Some vehicles run with only one light, and more than a few with NO LIGHTS AT ALL! (Vehicles without any lights are quite common in city driving!) Slow moving vehicles, stopped vehicles, bicycles, and pedestrians may not be visible at all. Neither will the many road hazards. Avoid driving at night, or if you have to, exercise extreme caution. And carry spare headlight bulbs. Rough roads can do in your headlight bulb easily. They now sell halogen bulbs for the Bullet. I just got one and cannot yet tell you if it was a good choice. Considering road conditions, having a strong headlight can only help.
Carry a good first aid kit
At least you should be able to clean and dress scrapes and cuts. Do not expect any roadside assistance if you have an accident. Not only is there no ambulance service in most places, it is not uncommon for the bystanders to be afraid to offer assistance when an accident occurs out of fear of the police, and ignorance of what to do. Victims of serious accidents are lucky if they are picked up by their arms and legs and tossed into a local taxi and driven to a hospital. Spinal injuries virtually guarantee paralysis. Preventable bleeding easily leads to major blood loss. This is why avoiding accidents in the first place is so crucial.
Wear a helmet
The laws in some cities do require helmets, but may not be enforced. In reality there is no real compulsion to wear helmets, and quite a few reasons no to. (They are hot, heavy, and awkward.) Still, considering the consequences of an accident without a helmet, you would be well advised to wear one. Helmets are readily available in India, but look carefully for a good one.
Have good Eye protection
Use a visor on your helmet, or get some good goggles. They sell the WWII dispatch driver type of goggles here, if you want them. You will encounter a large number of bugs while riding. A good sized dragon fly can cause serious eye damage, as can stone chips flung up by other vehicles. Also the wind can dry or blur your eyes.
Bring an International Driving Permit
The police in some areas (Goa, I've heard, is bad) enjoy catching foreign tourists driving without a valid international permit. They are mostly interested in the "donation" you will be forced to cough up for them to look the other way.
Enjoy the Challenge
With most of the warnings out of the way, look toward the bright side. India is a fantastic, beautiful, and challenging country to travel in. On a motorcycle you'll have access to places, people, and experiences that few other travelers will. It will be a memorable trip. Be careful, and have a great time.