Air Filters - Universal Thread

[Ayson]

@Anupdas


A leaner mixture than needed prevents the engine from cooling sufficiently. The piston, cylinder and valves are cooled to a large extent by the fuel in the charge. Think how just the fins around the cylinder can cool the super hot valves or valve seats sitting in the head?


Like you said, an over rich mixture is a waste of fuel. Just like that a lean mixture is a waste of air!!! I'll make sense. Imagine the ideal mixture of 14.7:1 (air:fuel by mass). Any air more than 14.7 would mean fuel less than 1. Now you have created a situation where there is unnecessary air in the cylinder. The oxygen in that air is useless because there is no fuel for it to react with. It takes up place in the cylinder with no useful purpose.


What you said would make sense in higher altitudes. But you are not really changing the mixture. When the settings are adjusted for change in altitude, what we are doing is, reducing the fuel supply to accommodate the reduced air supply so that the ratio remains the SAME.


I'm not sure, someone correct me if im wrong.


Now, i have some questions about the aftermarket free flow air filters. When anybody wants to upgrade to one of these, the first advice given is to upjet. I have read in many posts that a jet of a higher diameter is to be used. I understand that since you are letting more air in, you should also let in a proportionally higher amount of fuel to keep the ratio constant. But here are my questions.


1) In a carburetor, the throttle handle controls the butterfly valve near the venturi. The more it is opened, the more air is let past. Now as far as i know, the fuel is drawn through the jet into this airstream by the low pressure created in the venturi. The more the throttle is opened, the faster air flows, the lower the air pressure, and a proportionally higher amount of fuel is drawn. So, Eg. : 50% open throttle, would create pressure X in the venturi with stock air filter, would a free flow filter cause the air pressure to not drop to X, due to lower air velocity, hence drawing less fuel due to lack of suction?


Or, will it be the same drop in pressure since the throttle position is the same and air velocity is the same? What exactly causes the mixture to change without upjetting WRT carburetor workings.


2) Why upjet? Why cant we just use the volume control screw?

[PRANAV D]

@abhijeetbuzz great! but did you upjet the carburettor after installing K & N? If not then u should as soon as possible.

[abhijeetbuzz]

Intsalled K&n on my pulsar 150 dtsi...

Intsalled K&n on my pulsar 150 dtsi...
Sounds great....
But there is a humming sound from the engine.. mechanics say that it is magnets sound... but I doubt it as I have changed the complete magnet assembly...
Also FYI... engine was opened once when the earlier magnet and bearings were out of condition... mechanic thought it was a engine seizure and opened the whole engine for it
.....

[aarunn]

any one using Green cotton filters?

[whiteknight]

Its A FI K&N will not support it it will give multiple lags.......

How about a RTR180 How do you fit a K&N on it because it cannot be connected to a carb directly or it will make hideous sounds and not on the tube because it will decrease fuel efficiency.

[Anupdas]

I have doubt about leaner mixture producing more heat. In the air-fuel mixture the limiting case would be the air flow, so a carburetor is tuned in such a way that the air available is sufficient to burn the fuel completely.

By installing a K&N filter air flow increases and hence more fuel can be given to engine and thus more power. A rich mixture will be wastage as there is unburned fuel. But in a lean mixture there is more air than necessary to burn fuel, so 100% fuel is utilized.

While touring on high altitudes, the oxygen content in air would be low so wouldn't it be advantageous to make air-fuel mixture a little on the leaner side than optimum?

[sherpunjabi]

Bajaj Pulsar 220 Dts-I Rejetting!

Hey guys. I'm new to the xbhp forums... I got a question here. I bought my Pulsar 220 Dts-i last september and I installed a K&N into it in December... I'm thinking or re-jetting the carburetor. Now the only thing I'm worried about is if re-jetting will mess up the engine or not. And I know the warranty will be voided but are there any ways around this? I was thinking that if something happened to the bike I could replace the new jets with the original jets and then take it to the Bajaj service. Do you guys think they will find out that I had done something to it? And also in rejetting do they have to drill anything or drill bigger holes in the stock carburetor? And does the carburetor of the 220 have any serial numbers? BEcause if the rejetting does mess up the engine I can buy a new 220 carb and put it in... so then I could get around the warranty voiding part. Please guys any help would be greatly appreciated. THANK YOU!

[sree_unicorn]

Air filter for Unicorn

What is the advantage of viscous air filter over a paper air filter? The new CB Unicorn comes with viscous air filter,can we fit this type filter into 2008 Model Unicorn?
Help me on this.

[joelkraju]

itz better you upjet your bike to 117.5 atleast
itz the jet size of pulasr 180 ug3
so that in future no problem and u can et gud pick up also

[PRANAV D]

i got a k&n filter RC-1060 fitted on my unicorn a few weeks ago. After fitting i just adjusted the air/fuel mixture did not upjet. My bikes performance has improved marginally and no problems of overheating or jerking at high rpm like what happens in lean mixture. Do i still need to upjet my carb to larger main jet? (stock is 115)

[gautam]

what do you mean by "opening more in each gear " is it more acceleration ? if yes then i don't think so . the mix might be too lean at higher Rpms and you need to Upjet to fix that

Thanks puneet, i meant slightly higher revs

[diehard]

hey guys i was plannin to put a k&n rc1100 on my 220 fi just for a couple of days and then return to the stock wanted to knw if i need to set it for richer mixture and if yes wat shld it be ??

[Puneet1]

Any advice....anyone ??

what do you mean by "opening more in each gear " is it more acceleration ? if yes then i don't think so . the mix might be too lean at higher Rpms and you need to Upjet to fix that

[gautam]

So if i have the follwing setup...

K&N Filter in Airbox + Stock Jet = Slightly leaner mix

..will my bike open slightly more in each gear. I am not expecting phenomenal change, i only want the bike to open more in each gear...

Any advice....anyone ??

[vineeth aredath]

hi guys

Can i use k&n on my fz16

Will it affect its performance or not. Also is it good or bad for engine life.

yes dude you can use k&n on your Fz16, K&N rc1060 one of popular conical K&n and will be a direct fit, afaik there wont be any highly noticeable improvement But am sure that there will be a great Psychological gain

search threads in general biking discussion forum for further details