KNOW WHY THERE IS BULGE IN EXHAUST PIPE OF DIRT BIKE !

Dirt bike engine uses two stroke gasoline engine.The exhaust pipes of dirt bikes are shaped strange. They expand into a wide diameter and then shrink down to a very small diameter where the exhaust gasses emerge into the environment.In this article we will understand why these exhaust pipes are shaped in that manner.

That bulge is called an expansion chamber, and it is used to increase the horsepower of the engine . This technique only works on two-stroke engines, which is why you see it on a lot of dirt bikes but not on street bikes. Most street bikes use four-stroke engines.

The basic idea behind an expansion chamber is to use the momentum and pressure of the exhaust gases to create a pump that squeezes more air and fuel into the cylinder during the intake stroke. It does the same sort of thing that a turbocharger does, but it does it without moving parts.

How it works:

While moving downwards after ignition, the piston exposes the exhaust opening, and the burned gas streams into the exhaust pipe like a (high pressure) shock wave.

Due to the inertia, this gas will create a slight vacuum wave behind it, which helps to suck out more burned gas, but also fresh gas as soon as the intake opening is uncovered. 

The first cone helps to increase the vacuum: When the gas travels through the pipe with a certain speed, it travels through a certain volume per time. If the cross section is increased and the speed remains the same, the wave travels through a larger volume. This creates more vacuum volume behind the wave.

Now we have fresh gas in the cylinder, but also in the manifold. The shock wave now hits the right cone and gets reflected.That is, you now have a shock wave running towards the cylinder. It hits the fresh gas right in the moment when the intake opening is covered by the piston, and presses this gas into the cylinder. When the piston covers the exhaust opening, too, the fresh gas already is under some pressure.

This way, the exhaust forms some kind of compressor, increasing the volumetric efficiency / power of the motor.

KNOW WHY MANHOLES ARE ROUND IN SHAPE !!

You might have noticed that most manholes, and their covers, are round in shape.We will discuss the reason behind the round shape of manhole cover in this article.

1.Mishandling the Manhole cover-A round manhole cover cannot fall through its circular opening, whereas a square manhole cover could fall in if it were inserted diagonally in the hole.

2. Rolling the Manhole Cover -A round manhole cover is easily moved and rolled.

3. Strongest shape-When a square or rectangular manhole cover is subjected to sudden vertical compression (think of a very heavy truck driving over it), the weakest spot, the center, isn't equidistant to all supporting sides, especially the corners, which give support from two directions and are thus the strongest points (for similar reasons, experts recommend you stand in the corner of a room during an earthquake). With a circular cover, the center is equidistant from all supporting sides, and due to the gradual curve, any point along the edge gives almost as much support as a corner on a square cover. Circular shape results in uniform stress distribution.

4. Circular covers don’t need to be rotated or precisely aligned when placing them on the opening.

5. Round tubes are the strongest shape against the compression of the earth around them, so the cover of the tube would naturally be round as well.

6. It’s easier to dig a circular hole.

KNOW WHY HEADLIGHTS OF NEW MOTORBIKES ARE ALWAYS ON !!

You might have seen all two-wheelers which are launched after 2017 have their headlights always ON, we do not have an option to turn it OFF. In this article, we will discuss the reason behind always ON headlight in two-wheelers.

All new motorcycles and scooters that roll into the market need to feature AHO from April 1st, 2017 onwards. Most two-wheeler manufacturers term AHO as All-time Headlight On or Automatic Headlight On system. As the name suggests, new motorcycles and scooters which are sold and registered after April 1st, 2017 need to have the headlights on at all times. Yes, even during the day.

This is in compliance to a notice issued by the Road and Transport Ministry of India. All new bikes equipped AHO will not have a button to switch on the headlight, since it will always be on, but will only get high-beam and low-beam buttons along with the pass switch.

Why headlights need to be turned ON always:

This is a safety measure initiated by the ministry and is followed in many international countries. The idea behind this is that keeping headlights on throughout the day, even when the sun is nice and bright, makes spotting two-wheelers easier on the road. So, others on the road can see the motorcycle or scooter from a distance. It is also helpful during tricky light conditions during dusk, dawn or in case of sudden clouds casting a shadow. In short, it is a safety measure to increase the visibility of the two-wheelers on the road so that accidents can be prevented.


This will strain two-wheeler batteries a little more, but without hampering the battery in any way. Most modern motorcycles and scooters use advanced battery and alternators system, which can comfortably manage the extra load. This will no way alter fuel economy either. So, no need to worry.

Now-a-days most of the companies are coming up with DRL (Day-time Running Lights) on their motorcycle headlights as seen on the Bajaj Platina. This is basically a small, but fairly bright strip of light incorporated in the headlight console. This strip remains illuminated even if the headlight isn’t switched on, so that the on-coming traffic can clearly see the motorcycle or scooter approaching.