Tuesday, May 25, 2010

Tuning Yamaha FZ 16 Carburetor

Note: Follow the below instructions at your own risk. However I will be here to help if things go wrong. 

Tool required: Screwdriver

Things to do before you tune your bike.

1. Clean the air filter.
2. Clean spark plug and make required adjustment.

The first thing you should know when it comes to tuning Yamaha FZ 16 is understanding which jets control the fuel flow at a particular throttle position.

Throttle positions:

Closed to 1/4th open: Fuel screw on the bottom of your carb (Pilot Jet).
1/4 - 3/4: Needle Jet
1/2 - Full: Main Jet

Here we will discuss only about the Fuel Screw.

Where is the fuel screw in Yamaha FZ 16?

In Mikuni Carburetor the fuel screw is close to the engine side on the left. It a minus head in golden color.

Before you touch the Fuel screw:

It’s important to note the current position of the fuel screw.

1. Turn off the engine.
2. Turn the fuel screw clockwise while you make a note of the number of full turn it took to reach the close position (Turn the fuel screw clockwise till it closes).
3. Now put the fuel screw back to the default position (Turn it anti-clockwise)

How to adjust fuel screw?

Turning the Fuel screw clockwise will reduce fuel flow: Lean mixture.
Turning the Fuel screw anti-clockwise will add more fuel: Rick mixture. 

Let’s get started:

1. We need to warm up the engine. Not just starting the engine; Ride your bike for 10 to 15 minutes.

2. Bring the bike to fast idle (Turn the idle screw clockwise till the RPM hits 2000)

3. Now use the screwdriver to slowly turn the fuel screw clockwise till the engine RPM drops. Note some bike will still run when the fuel screw is completely tight.

Now the bike is running at the leanest point.

4. Now slowly turn the fuel screw anti-clockwise 1/2 turn at a time (180 degree or half turn)

Wait and listen to the engine RPM and continue turning anti-clockwise 1/2 turn at a time.

You will hear the engine rpm begin to speed up.

Stop turning the fuel screw at the point when the engine hits peak rpm (At this point the exhaust note will be crisp). 
Peak rpm is when the engine runs the cleanest and fastest. 
When you reach that point, turning the fuel screw anti-clockwise won't increase the rpm further.

Note: Turning the fuel screw anti-clockwise further from the above point, the rpm will stay up but the exhaust note will become dull.

5. Now turn the idle screw anti-clockwise to bring the rpm back to 1000 or 1500.

6. Now take a test ride. 

Did I get the correct Air/Fuel mixture?

1. Twist the throttle the response should be quick and crisp. 
2. There should be no hiccups when you ride.

What fuel economy can I expect on Yamaha FZ 16?

40+ Km/lt if speed below 55kmph.
35 to 40 km/lt if speed is 60 to 80kmph

My Bike Photo 1 

My Bike Photo 2


  1. My bike runs great now...Thanks :)

  2. I am gonna try out your tuning instructions. I need to know if rear disc brakes can be retrofitted to the FZ16?

  3. This comment has been removed by the author.

  4. gr8 article...

    can you guide me how to tune my FZ-16 carb in high altitude?
    will reducing the fuel (i.e, making it lean) will do by clock wise movement of the fuel screw?

    can it be done in trial & error method only by seeing the performance & compression i am getting from the bike?

  5. hi,i hav hailed into a problem.today when i checked, my fuel screw has jammed and i can hardly move it form its postion ..do u hav any idea regarding thi???:( can u plz help me out

    1. Same problem with me
      What did u do to free the screw??

  6. For Starters: Simplest way to adjust airscrew for optimal pickup and milage
    1.Note down / mark the correct position of the airscrew.
    2.Turn airscrew two full rounds anti-clock wise
    3. Set the rpm to 1500
    4. wait for 15 seconds and apply little throttle. if the bike stops then tighten the airscrew 1/4 (quarter circle).
    5. Repeat point 4 until your bike is stable.

    I am getting 50 milage on my FZ

  7. how many turns from close is the default A/F settings of FZ ?

  8. where's the air screw in FZ carb?

  9. 3. "Now use the screwdriver to slowly turn the fuel screw clockwise till the engine RPM drops. Note some bike will still run when the fuel screw is completely tight."
    1: RPM drop to 1000? Or
    2: turn the fuel screw clock till its totally close tight?

  10. wht is the default number of turns of fuel screw in yamaha fz16

  11. It depends on climatic conditions...Default may be between 2.5 to 3.5 Full rotation.

  12. Why does mine turning clockwise towards closing will inc the rpm instead? And anti clockwise dropping the rpm? It's totally opposite from the guide. Help please.

  13. my fz emit smoke,only 10,000 km completed

  14. R u sure i will get 40+ milage. What will happen if the fuel screw tight (clockwise). Will it increase milage..

  15. i did not counted the turns of fuel screw while rotating clockwise ! and should not we touch air screw ?
    presently fuel screw is 1 turn open from full tight, what will be the mileage or performance? ...

  16. Will it not effect the pick up or acceleration of the bike ??

  17. my fz is giving me 55kmpl even before tuning in city...

  18. one doubt. wats that screw on bottom. is that related to overflow . .

  19. Yes thats the drain out the fuel.

  20. I have fz16, done 20000km, i am facing problem that, when i reduce the speed, getting trouble like, eng gets off or even on stared position no rpm goes up.....Local mechanics says,

  21. even mechanics also confused, because they have tried several ways and open carb more than 7 times, but nothing....and also one time they have put small cable in to main jet to reduce fuel then works well but low engine power....so what can I do??/

    1. hi Gob Thurai .. i have the same problem in my bike also..did u find any solution ?

    2. Hi I also have same problem with my fzs
      Plzz help me !!

  22. thanks this was very helpful. i tried this, but i tried after installing a k&n , i tuned to 3000 rpm n did as suggested by xbhp, but a funny thing i found out that i had to screw 4 half rev to get the optimal mix, at first in 5 half rev the rpm got constant then i drove for a test ride, then again i screwed 1 half more rev so as to match xbhps suggestion (mentioned 3-4 ful rev) but after 3 ,4 iteration at last i got it in 4 half rev, but i heard the stock rev is 5, so its kinda fishy to me that is it really safe for me to drive with 4 half rev, since it can heat up the engine ??? plz guys i need some advice in this !!!!!

  23. hi Gob Thurai .. i have the same problem in my bike also..did u find any solution ?

  24. Gob Thurai and Rishis3D:
    From what u said, I understand that you are running on Rich mixture.
    1. Go to a trusted mechanic or yamaha service center and ask them to tune the carburetor to "stock"/original setting.
    2. Set the engine idle speed to 1300-1500rpm.
    3. Check your Air Filter for any dust or spoilage.
    4. Check clutch free play and also Throttle(accelerator) free play.
    5. Before you start your bike for the first time in a day, set the choke lever to "ON" and wait for 20 seconds. Then start riding.

    After all these if you do not find any change, then there may be a bigger fault. Contact Yamaha Dealer

  25. i tried this... but i fully tight the air/fuel mixer screw the engine still running... any idea? so i guess i need to change the needle ? right?

  26. the original tutorial --- http://bikeadvice.in/tuning-carburet...#comment-95481

    review: performance is not so good in the long run and mileage lessens (33 kilometers per liter on 40 - 100 kilometers per hour).
    tuning is not optimal.

    **************************************************************************************************** ******

    the resetter tutorial --- http://bikeadvice.in/tuning-carburet...comment-100043

    review: performance is very much good and astonishing and the mileage improves (37 kilometers per liter on 40 - 100 kilometers per hour).
    this is the best. maybe fuel consumption will reach up to 40 kpl or more if you maintain the speed of 40 - 60 kilometers per hour.

    good luck to everyone.

    to God be all the glory!

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  28. http://bikeadvice.in/tuning-carburetor-optimal-performance-fuel-efficiency/#comment-100043

    this is the link to the resetter tutorial. highlight the entire link/address, right click and choose "Open in new tab or Open link in new tab".

  29. i was turning the fuel screw to note the current position and the screw driver slipped and i lost count... now what to i do

    1. Hav u readjusted it ? What's the default rotation?

  30. Thnkz cheene for ur valuable guideline. I m facing tremendous problem in mileage. My fz is 4 yeara old. But after changing a part (piston of curburator) my mileage dropped to 14 km/l !!! I changed the spark plug, checked by mechanic. Even though the mileage is 14 km/l. Plz give me some guideline.

  31. My fz run aroud 60000 and now I change my silender kit and its give me 25 per liter milage what to do can I have to change my carborater also please give me solutions

  32. By changing the carburetor of fzs the millage will increase or not ????

  33. Thanks ... it helped me alot ... good job .... i did better than my mechanic with your guidance