How to tune your carburetor

I’ve learned to tune my carburetor through experience and reading online.

Please be reminded that any damage caused to your scooter/motorcycle while attempting to follow this guide is your fault and not mine. Engines differ in setting and specification.

So please do this at your own risk.

What you need:

1. Flat Screw Driver

2. Spark plug remover

3. Steel brush (optional)

Steps:

1. Remove the engine cover, if you still have it. It’s easy, just open your seat and find the screws needed to be removed.

2. Locate your spark plug cap, remove it and inside you’ll see the spark plug.

3. We need to take a look at the condition/color of the spark plug tip first.

* If it’s brownish – then that’s good.

* If white, not good because the carburetor is not feeding enough gasoline to the engine and this could cause knocking and may damage and lead to a broken piston.

* If black, that’s good but it depends on where you’ll use your scooter. – We’ll get back to this later.

4. To remove the spark plug, you will need a spark plug remover.

5. Take a look at the sparkplug tip and remember it.

6. Using the steel brush, brush the tip of the spark plug (this is optional, but would be better so we can determine if we are successful or not in re-tuning your carburetor).

7. Screw the spark plug back on.

8. Start your engine and take it for a ride for at least 1 km or so. Ride it as much as you can and open the throttle as full as possible if you can , just be careful on the road.

9. Park your scooter, let it cool for a while.

10. Take a look at your spark plug tip once again, remember it could take a while for the spark plug color to change. Once you get the color we can then adjust depending on the weather, color, performance, and purpose of tuning.

11. If you are satisfied with the sparkplug tip color, then I suggest you leave it be. But if you’ll be going on long rides and want to be safe, we can adjust it a little bit.

12. Depending on the carburetor, it will depend on where we can find the air/fuel screw. This is used to adjust the fuel feed to the engine. Assuming your carb is properly jetted.

13. Now, I have a different technique in tuning my carb, after I take my scooter for a ride, I will then park it and put the center stand on, turn the engine on.

14. Using the flat screw, I will then adjust the air/fuel screw and listen to engine’s rpm. If it’s dropping then you’re feeding too much gas, if the idle goes way up, then you might be feeding too much air.

15. Listen to the engine and find the balance of the idle you want.

16. That’s the basics of tuning your carburetor. Congratulations. After a while, please re-check your spark plug tip color. Adjust as necessary using the air/fuel screw.

Source: https://miofinoguy.wordpress.com/2014/06/04/how-to-tune-your-carburetor/