When going on a really long ride (something that takes more than one day), make sure to equip yourself with a set of spare parts. Here's a list of essential parts that you need to carry with you:
1) Throttle, clutch and front drum brake cables
2) A puncture repair kit (spare tube for tube-type tyres) and a portable air-pump
3) If the trip covers more than a thousand kms of riding, carry the essential fluids (engine oil, brake fluid and engine coolant) for topping up
4) A couple of spark plugs
Training yourself in performing basic repairs on your bike will save you the time spent waiting for a mechanic, in case you are stranded. Head to your regular service centre or local mechanic to learn how to perform the same, before setting out on a really long ride.