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idle adjustment chinese atv 110cc Tao Tao

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idle adjustment chinese atv 110cc Tao Tao

spdjnky_42 spdjnky_42
New User | Posts: 2 | Joined: 01/12
Posted: 01/16/12
04:24 PM

Im sure this has been posted a million and one times. However, I cannot find a good picture of the idle screw on the Tao Tao carb. It will start and run fine but seems to have the idle set too low. It did sit for a while in the freezing cold and gas smelled like varnish. Before I tear this carb apart and clean it I would like to try raising the idle. There lies the problem. On the pass side I see three inset screws one at the top just above the bowl. One in the middle, and one just above the drain tube. would anyone like to help me re adj the a/f (this thing sounds like a coffe can with a nut in it) and raise the idle? Thanks!  

thejunkman thejunkman
User | Posts: 101 | Joined: 01/12
Posted: 01/16/12
05:07 PM

You need to check out my website.  I have two videos that should help you figure out what needs to be done.  First off you should probably clean the carburetor because your problem most likely is because some carburetor jets or passages are clogged.

Here is a tutorial on how to adjust the idle air/fuel mixture.

Here is a carburetor diagnosis video, in the future I may do a jetting video  
Check out my webseries

spdjnky_42 spdjnky_42
New User | Posts: 2 | Joined: 01/12
Posted: 01/23/12
01:03 PM


jessieherrera jessieherrera
User | Posts: 51 | Joined: 02/12
Posted: 02/12/12
04:02 AM

 Per your question the idle/air screw is located towards the front of the carb which is the closet point to the intake manifold (head/engine). It should be towards the upper part of the carb center (just above where it goes into the manifold). It should be the ONLY screw in that area. It may be vertical or horizontal on the LEFT side of the body. On some carbs they were located underneath towards the front(not on the bowl). If you still can't locate it please post a few pictures of the carb and I will respond. The only other screw you should have is the idle speed screw which raises the slide to increase idle speed. This is either on the linkage or the direct side of the carb where the slide is. It comes in direct contact with the slide. This one is usually close to where it needs to be to idle at the the right speed. If not then screw this one in to where the slide is slightly open to keep your engine running enough to adjust the idle/air screw. You should ALWAYS adjust the idle/air screw first (step one [#1]):
Carb jetting and adjusting:
First, always run the carb dry when you are finished riding by shutting off the gas at the petcock and let it idle until it stops running. This is the best practice for any small or industrial engine. You may have a Mikuni. Even if you don't many carbs are similar in design and parts. Mikuni carbs are very easy to work with. Make sure that you have no vacuum leaks whatsoever.
Usually, the bigger the carb, the smaller the jets.
With today's gas it is almost impossible to read a spark plug. It used to be that if they were a soft white to a medium tan the mixture was correct. Today, you may want to try this to get the right mixture.
Adjusting your carb/mixture/jetting:
1. The idle air screw always starts at 1 1/2 turns from closed. Let the engine warm up and open or close an 1/8 of a turn at a time. Give it about 5 seconds to settle. Continue until the engine reaches its highest RPM/speed. This is called your best lean idle.
2. The cutaway on the slide regulates your mixture just off idle. The different cutaways enrich or lean the mixture.
3. The slow speed jet regulates the mixture until the needle in the slide takes over. This is initially about 850-1000RPM. Increase the jet size one at a time where you get the highest RPM at that slide or throttle position, not RPM as this will change with jet size. You should feel more power at that throttle position. Your needle on your slide should not be active or at the taper.
4. The needle in the slide regulates the mixture to wide open throttle. The needle has a taper to it which regulates the fuel amount from the main jet. It also has a few notches that will raise or lower the needle. Raising position enriches. You will feel more power at that throttle position.
5. The main jet regulates the mixture at "wide open" throttle. Read below to adjust.
I have found that the best way to jet your engine is by what's called "seat of the pants performance".
Adjust the jet size by enriching the jet until you get the highest RPM/speed at that specific RPM/throttle position. An example would be the slow speed jet at let’s say, 850-1000 RPM though this will change with the richer jet so actually it's better to go by slide position.
The high speed jet you do by accelerating through the gears until you reach top end. Keep increasing the size one size at a time until you get the maximum speed and feel of power. Once that is reached go down one jet size.
With different pipes and types of driving as well as types of intakes jetting will change. Altitude is also a factor. An example of intakes would be velocity stacks or air cleaner inside configurations. Different lengths of these passages affect you RPM and acceleration. High performance demand will always require richer mixtures as moderate driving will perform better at leaner mixtures.
Good luck. Wink