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See, fitting a carb from P220 is possible, but better get it rejetted only instead of fitting a new carb. Get a Karizma Main jet for Rs. 153, whose size is #125, compared to your current 115 jet.

There is also an AFR screw on your carb, but that should be for minor changes. It can not handle the K&N level airflow...



Replacing a Main jet is a very simple process:

1. Switch off the fuel supply.
2. Open carburettor's bottom most cover, opening 2 screws in the process and let some fuel spill. (See the picture above)
3. You will see the main jet installed upside down. Unscrew it by a small length screwdriver, and re screw a new main jet into the hole.
4. Rescrew the bottom cover back to the carb. Done.


NOTE: To maintain your engine's safety, I suggest you don't keep your K&N RC1060 filter open, in direct contact with air.

Put it in a self made/ other airbox which protects the air coming in from direct dust, water, etc. Because dust will affect it, and excessive dust will make filtering ineffective, and destroy your bore/ piston.

If you can't make an airbox, remove the K&N forever. I removed it too 2 months after I installed it on my P180 way back in 2009.

The amount of power a engine produces depends on the amount of fuel in the air entering the engine, called the air/fuel ratio or AFR. The ratio is 15.4 : 1 for good fuel economy (15.4 parts air with 1 part fuel) and 12.6 : 1 for good power. 14.7 : 1 is considered an ideal compromise.

Since you have installed a K&N, you have effectively increased the amount of air entering the engine without increasing the amount of fuel it carries with it. Now your engine is running lean with a ratio greater than 14.7:1 & hence producing less than optimum power. To compensate for this increase in air quantity and get back to either 14.7 or less you will need to re-jet which basically means installing jets which will allow more fuel to pass through them.

A lean engine also runs hotter so you run the risk of damaging components.

It increases engine life. It makes the engine stable, cooler and safer.

In a way, it increases performance too, as without this rejetting you may not be able to reach your top speed.

One side of the story. Rejetting (and doing it correctly) does what Samarth rightly said

Rejetting and over fuelling the engine would mean more un burnt fuel, lower mileage, and a long list of problems

Re: Pulsar 180 carb rejetting

u had installed race concept carbureator?

Re: Pulsar 180 carb rejetting


Remove the k&n as soon as possible. Trust me, it reduces the engine life. I once used k&n on my p180 ug4 and then faced all sorts of problems. Have spent a lot in rectifying. Your bike is only 1.5 years old, so by installing k&n u're rendering the warranty void. P180 has sufficient power, so the increase in power after this modification is pretty insignificant. And these modifications have to be done by expert mechanics. As u say there aren't good mechanics , i suggest u get the stock filter back in place as soon as possible.
If u really want to do this modification, wait for the warranty period of 2 years to get completed. And put it in an airbox as Samarth 619 said. I dont think its possible to make an airbox. What u can do is remove the filter from the original air-filter box, cut it open at the sealed edges, fit the k&n and then stick the cut-part of the box like a lid using glue or fit it by getting clamps made and screwing with bolts. But in the process u'll be damaging the box. So in future if u want to go stock, u'll have to spend around 1500 bucks for a new box.
But bear in mind that by doing this modification u'll be reducing the engine life and if not done by an expert mechanic u may end up screwing ur bike sooner.

Ride safe

Re: Pulsar 180 carb rejetting

please do not go in for the karizma jet as it is using a keihin carburetor while the pulsars use mikunis , the numbering system of both manufacturers are different , by puting the kehin jet you will be down jetting your carb making the mixture further lean please go through the foll link for the comparison between the two FAQ Mikuni vs keihin vs dynojet

Re: Pulsar 180 carb rejetting

The marking by Hero MotoCorp is based on Mikunis only. I have seen the #125 jet myself, held it against the 117.5 in my Pulsar, and I've installed it too, in my own bike. So, I can confirm that the #125 will be appropriate for rejetting, and it is definitely bigger than Pulsars' main jets, mostly all of them.


Guys, Do remember that the K&N company is a good one, but it is not an Indian company. While giving out the Million Mile Warranties that won your hearts, K&N did not consider Indian conditions, and specially not Indian carburetors, instead of Closed Loop Fuel Injection systems of the USA. The Indian conditions are more dusty. Plus, we the bikers don't use airboxes so the entire load of dust falls on the delicate filter itself. Plus, the Indian carburetors can't adjust fuelling themselves, to compensate for additional airflow.

Hence, rejetting and a custom (preferably porous) airbox which protects from dust to an extent is almost a necessity. I'm talking from my own experience of my Pulsar. There could be things I might be missing though...

Re: Pulsar 180 carb rejetting

the jets for karizmas carburettor are made by keihin not hero so its highly unlikely that they will follow the coding system of their competitor just for the sake of hero,
as for the dia of the hole compared to the mikuni jets, each manufacturer designs their jets based on the basic flow parameters and rates of their carburettors, the karizma jet will give its max flow when fitted to its carburettor , it may not give its max flow when its fitted to a mikuni, . im no expert in this field but the above is what i know and what i have realised..

PS: i concur with you on every word you said about k&n , they are not suitable for indian conditions . but then indians are indians always running after Phoren stuff