Carburetor Thread

[bublu]

Re: [UT]: Tuning your Motorcycle Carburettor.

Dear xperts,
Previously i have problem with my pulsar200 dtsi carburetor diaphram and i have replaced my carb with bs32(220 carb) now i'm having intake manifold leakage m.i want to know that 220 carb intake manifold will be a direct fit on 200.please do reply me kindly waiting for your reply
Thanks in advance
From shravan pathipak

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[royal racer]

Re: Carb tuning

Altering the air fuel mixture ratio will result either rich or lean mixture. Increasing the petrol means more fuel than the ideal ratio which will result in a rich mixture. Rich mix lead to incomplete combustion, more carbon deposits, fuel wastage.



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I know what you trying to say but my question is different.

[rxdude]

Re: Carb tuning

I want to know If i tune my carb and increase the petrol how does it affect ..
it increase petrol flow in pilot jet.
it increase petrol flow in main jet
or All jet petrol flow increase.

Altering the air fuel mixture ratio will result either rich or lean mixture. Increasing the petrol means more fuel than the ideal ratio which will result in a rich mixture. Rich mix lead to incomplete combustion, more carbon deposits, fuel wastage.



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[The Monk]

Re: Carb tuning

I want to know If i tune my carb and increase the petrol how does it affect ..
it increase petrol flow in pilot jet.
it increase petrol flow in main jet
or All jet petrol flow increase.

Query Approved and Merged

[royal racer]

Carb tuning

I want to know If i tune my carb and increase the petrol how does it affect ..
it increase petrol flow in pilot jet.
it increase petrol flow in main jet
or All jet petrol flow increase.

[Rakesh Rok]

For those of you who think that a richer mixture is a gateway for more power, it may be noteworthy of a mention that even a richer mix is damaging and causes faster wear and tear.

Okay let me just agree with you that, I just got my Honda Unicorn carburetor tuned for a richer mixture, believe it or not, I had a race with an RTR180 soon after I got it serviced by the Mechanic and I was surprised to see that my Unicorn outperformed the RTR180 and was quicker from 0-60 and went till 85-90 after which the RTR took over (the last time I had a race with an RTR180 which was not in a good condition, my bike was just behind it, and this is a new bike, just around 10000k finished yet) and also a thing of note, is that the top end, yes the top end of my bike has been increased by 10 kmph, earlier with much effort, it was going to 109, now it reaches up to 120 and few more if pushed over the limits, can you explain it to me how these things happened if it not for the rich mixture. . ? My bike is around 6-7 years old now and I did not experience much of a fuel efficiency downgraded after the carburetor tuning (think it's an old bike and got fixed to that sought of mileage). . . Please don't say me that both things are the same as earlier I had tested before the tuning as well and also after the tuning to see my bike's performance. . .

[PS: Do correct me if I am wrong in anywhere]

Thank you.

[sangeethskumar1]

can any of you tell the no of turns that would be optimal for p180 ug4. What does a turn means..?? is it 180 deg or 360 deg. i do most of my bikes work. but the carb adjustment is twisting me a lot.

[superbsalil_02]

cant get rpm constant on my p220.......
after going to leanest setting can i take 1 or 2 turn fast??

[rprathin]

i have question for how to tune yamaha gladiator because when i completely tight the fuel screw than nothing happens.....

[Ramborider]

my pulsar 150 classic doesnt tune by that fuel screw,i had changed pilot jet also but it dont get set properly,when release accelerator it get off and after or some time engine speed increases prematurely so what would be problem for this??
i had using 12.5 pilot jet while before that it has 17.5,as i have read from pulsar dtsi workshop manual about pilot jet size,but i have doubt is it same for old model or not mechanic told that have to change carburettor!!please help me out any one here having pulsar 150 classic who would having idea about size of pilot jet???

[pranjal chakraborty]

Can the carb be tuned by checking the co2 level? And according to the co2 we can tune the bike to have a perfect tuning

[UTKARSH STUNTY SHARMA]

So ,
i figure most of us are still riving around carburetted bikes and at some point of time , some dumb ass mechanic will screw it up for you (like a Bajaj Auth Service for me ) , or some drastic altitude changes will leave you feeling powerless. This goes to say , that your carburettor will be out of tune .

So , while i have kinda figured the trick , i m sure none of you wanna be slaves to these headless mechanics waiting to tune a blunder for you .


A little Guide to tune you 4 stroke CV carburettor for the optimal ( Not power oriented ) air fuel mixture.

There are mainly two screws used for the tunning of a carburetor

1.Fuel screw(4 stroke) or air screw (2 stroke)
2.Idle Rpm screw

The main difference between two stroke the fuel screw is that for the fuel screw(used in pulsar etc) Clockwise tightening makes the mixture lean , and anticlockwise loosening makes the mixture rich.

For two stroke bikes using an air screw the setting is exactly opposite.



Judging the air-fuel mixture for the bike can only be done on a warmed up engine.

Warming up the engine

1.Drive for atleast 10-15minutes before trying to adjust any of the carburetor setting.
2.Especially for CV carburetors, used in the pulsar, use 1/2 throttle on an uphill for 1 minute. ( alternative )

Setting the mixture

1.Set the idle screw at 3000rpm
2.Now adjust the fuel screw for the leanest possible mix without stalling the engine.
3.Now after adjustment is made the rpm becomes constant
4.Now , adjust screw to tune within the lean range
5.Decrease idle rpm to about 1100
6.Check the throttle for a quick and crisp response. The crispiness is important
Also check for instant start


After warming and adjusting , drive for a while to check the spark plugs for the following signs
1.White Deposits : Lean Mixture
2.Black deposits : Rich mixture
3.Sandy side of chocolate brown : Ideal mixture.

Please note that the fuel mixture is always checked by driving between 1/4 th and 3/4th of the total throttle twist. This also goes to imply that the throttle body must have a uniform response to the same twist at all levels and is working perfectly.
The other , not so accurate way to check the correct mixture is the silencer or exhaust fume . Place your hand at the exhaust as you rake the engine after 1/4th of the throttle .

1.The sign of the optimal mix is that your hand feel slight warmish moisture as the throttle is increased a bit . Then check the same sign at constant throttle.
2.The very heat or temperature of the fumes at the upper limit of the power band should not feel too much to keep the hand there for about 10 seconds.


A few signs for your carburetor out of tunning
1.RPM rises fast but reduces slowly : Mixture is not optimal , usually on the leaner side.
2.Grunting sound (too much torque) : Rich mixture.
3.Engine knocking at low rpm without power : Lean
4.Not enough power , overracing at high rpm for same speed : Clutch setting req . Mix is a little lean



A Lean mixture is usally more harmful than a richer one . This is because , the engine is knocking at a higher rate for the same power . Thus the high compression damages the pistons causing holing(hole in the top center of the piston).It also jerks the entire combustion chamber which may loosen the o-rings as well as cause uneven wear.
For this reason it is necessary that you always try to keep the needle in the powerband for medium and overdrive gears, and also never try and keep the bike in the same gear for thought of better efficiency.

For those of you who think that a richer mixture is a gateway for more power, it may be noteworthy of a mention that even a richer mix is damaging and causes faster wear and tear.

Hence engine life is reduced though it will function better than a len mixed carburettor. In case performance is what you look at , Jetting of the carburettor is the right way to go. It is basically increasing the fuel pipe radius as well as the air pipe, to allow for a greater fuel flow rate. The most significant increase of jetting is felt at the top end , where the limiting fuel flow is increased, thought a difference is also felt throughout the entire RPM range.

However , once you drive a day or two , you will figure if your setting is correct or not . If the mixture is the optimal one then just a single anticlockwise turn ( richer) or maybe two will give you a reasonable boost in the power , though naturally you are sacrificing the Fuel effiency , although it wont matter much . But , repeat , test the optimal setting for atleast two days , before switching to the optimally rich setting . Coz knowing what is right is the only way to know , know what is beyond right.





Towards biking Independence......

Cheers!

PLzz tell me which carburettor size i need to upjet my apache 180 ....i have a jet .its written k118s on the side walls of this jet urgent reply needed

[Lonely Rider]

Hello,

I am looking pout for a BS 29 CArb for my Thunderbird. Alternatively would like to have a carb of Pulsar 180 also.

Kindly let me know if it is available.

[Honda_CBF]

Carb tuning like FUEL INJECTION

Guys, got some product info which help carburetors to perform like fuel injection while googling..
there are many products in this site. they say;
*there will be no need to re-jetting if you upgrade your air filter & silencer to Free flow
*best balance between mileage & performance
*easy tuning
*no effect of temperature & altitude; And many more
go through this for all details:
Thunder Products - Performance carburetor and clutching for snowmobiles, motorcycles and ATVs.
Thunder Products - Performance carburetor and clutching for snowmobiles, motorcycles and ATVs.
Thunder PowerJet Performance Carburetor Clutching Snowmobile Motorcycle ATV Improved Fuel Efficiency

[abhisheklakhanpal]

Karizma Boi,

If the RPM goes up to 2k , then its normal .

I have been riding a ZMA and this is the way it is .

The ZMA carb is designed to do so .


Hope this helps.