In the next 5-10 years there is every possibility of getting many diesel engined bikes into actual production.
At present Enfield Bullet is making the Bullet TAURUS diesel motorcycles with a 325 cc single cylinder diesel unit and the same separate gear box of Bullet standard bike.
It is very popular in rural areas especially among the Milkmen fraternity who would load it with around 3-4 quintals of Milk/ cans utilising every bit of its high torque. Still it returns anything between 60- to 65 kmpl of diesel.
It is bulky and there is lot of vibration and torque jerk as you race the engine a little.
Many people are mulling an idea to put a two cylinder diesel unit with fever vibes and high rpm to enable the bike get a petrol like character.
One possibilty is to borrow the new TATA Ace pickup 700 cc two cylinder engine which they have developed after carving out the 4 cylinder Indica diesel 1400 engine.
The engine is very silent like a petrol sibling and there is no visibile vibes as two pistons and a balancer shaft counter the vibes produced by each cylinder.
Well there are many other engines like the local Crompton greaves or the loombardini twin cyl diesel