Question about 2003 Yamaha YZ 125

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Need spects for carburetor main jet on mikuni ucal and spects for pilot air jet 1 and pilot jet 2

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Http://www.cmsnl.com/yamaha-yz125r-2003_model11245/partslist/A-12.html

Site above has all the parts and specs for your bike. Jet ranges are large for a YZ as many mod's are available and riding conditions contribute largely to a peaky 2 banger. Start with #40 pilot, and #420 main. Trial and error from there. Cheers.

Posted on Apr 27, 2010

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Posted on Jan 02, 2017

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Can't get my carbs to tune on a Suzuki gs550t 1981 carbs rebuilt and cleaned shimmed valves new head gasket still no joy?


Hi, Dave if you have changed your fuel delivery system, air filter size or flow rate, mufflers or exhaust system or a significant change in altitude your carburetors need re-tuning and if your fuel system (gas tank, filters, fuel valve and carburetor) is contaminated with ethanol sludge, varnish, rust, dirt, water etc. or your bike has been sitting for months or years without running these components must be "PROPERLY" cleaned and reassembled "CORRECTLY" before any adjustments can be made. Tuning your carburetor is fairly simple once you understand the basic principals. You engine is a simple airbox sucking air in and blowing it out, it is finely tuned at the factory for maximum performance once you upset that delicate balance by changing air filters, camshafts or exhaust systems your performance may go down the and the engine may run poorly, you need to compensate the air-fuel mixture in the carburetor in order for the engine to run smoothly and at peak performance. If you are running multi carburetors you need to sync them first and make sure your air cleaner element is clean and dry for paper elements or lightly oiled for foam and meshed elements and properly installed. Here is how and where you compensate trouble: "TIP" if your engine "BOGS" your not getting enough fuel.
1. Closed to 1/8 throttle is managed by the air screw and pilot/slow jet.
2. 1/8 to 1/4 throttle is managed by the air-screw, pilot/slow jet, and throttle slide.
3. 1/4 to 1/2 throttle is managed by the throttle slide and jet needle.
4. 1/2 to 3/4 throttle is managed by the jet needle, needle jet, main jet, and air jet.
5. 3/4 to wide open throttle is managed by the main jet and air jet.
6. Wide open throttle is managed by the main jet.
If you are running lean, spark plug electrode color is white, engine runs hot and feels like it is starving for fuel you need to go up on the jet size or move the c-clip down one notch. If you are running rich, spark plug color is black or dark gray, the engine runs cool, and bogs down when accelerating you need to go down on jet size or move the c-clip up one notch. When your carburetor is properly tuned for maximum performance your spark plug electrode will be a light tan color like coffee with cream. If you prefer fuel economy over performance you can go down on main jet sizes until a satisfactory level of lower performance is acceptable versus MPH, your spark plug color will be whiter and your engine will run warmer. These tuning adjustments will only make improvements if your intake and exhaust system have no air leaks or sealing issues and the entire electrical system is in proper working order and you have no mechanical issues.
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I need to know the proper tuning of ucal mikuni carburetor with mixture adjusting screw on bottom of cabr (beneath float bowl), an idle adjust screw and pilot screw (hopefully pilot fuel screw since s


Why did you need to clean the carb? Routine servicing of the aircleaner would keep the carb clean for life. The pilot screw should be 1.5 turns out approx. with a small adjustment either way. Idle speed is set to a smooth low idle.If this doesn't fix it have you got something in the carb not replaced correctly? The float needle/float assy? How did you clean it? Have you introduced fluff/dirt into the carb and did you blow it clean with an airline?

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Hi, Anonymous I am sorry you can't find the first and best tool you ever bought for your Bajaj but despair not for a mere $0 you can download another one. For more information about your issue, please visit the websites below. Good luck and have a nice day.
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Wont start


Instructions
    • 1 Remove the seat by unscrewing the bolts found on the four corners of the seat. Remove the clamps from the top of the air box using a pair of pliers to access and remove the air filter. The air filter is removed by unscrewing the wing nut and sliding the filter out of the box. Loosen the hose clamp that connects the carburetor to the intake manifold, using a screwdriver.
    • 2 Loosen the fuel delivery hose clamp with a screwdriver and pull the carburetor out of the Blaster. Before troubleshooting the carburetor, it's important to note whether you've made a significant change in altitude or a change in your exhaust/intake setup. If you've made an altitude change, installed an aftermarket exhaust pipe or modified your air box, the jets will need to be changed. Refer to your manual for specific re-jetting instructions based on your altitude. Your exhaust kit will provide a recommended jetting setup. Do-it-yourself modifications like removing an air box will require you to experiment with the jet setup until you find the right one.
    • 3 Disassemble the carburetor by unscrewing the bowl screws from the bottom of the carburetor. With the bowl removed, the float, pilot jet and main jet will be exposed. To remove the pilot and main jet, unscrew them from their respective holes. The main jet will sit in the exact center of the bowl, while the smaller pilot jet will be set just below the main jet.
      Use a blunt object like a stick or rod to push the bottom of the needle receiver assembly out of the carburetor. The needle receiver (which houses the needle jet) will slide out of the top of the carburetor along with the slide, spring, carburetor cap and gasket. The carburetor is now completely disassembled and ready to be inspected.
    • 4 Inspect the pilot jet for blockage, slide a thin wire through the pilot jet's hole, spray it with carburetor spray and blow the center hole with compressed air. Repeat this process with the main jet. If there is any blockage or wear, replace the jets. If you have made altitude changes or exhaust/intake modifications, insert jets that correspond to your changes as recommended in your manual. Note that this may take some experimentation with different jets to get the correct jet setup, as there are many jet sizes for different scenarios.
    • 5 Inspect the bowl, floats and ports for any signs of debris or gunk. If debris or gunk is found, remove it using a spray carburetor cleaner, soft wire brush, or thin wire (to insert into small orifices). If no gunk or debris is found, you've ruled this out as a possible cause for the starting issues, and can focus on the replacement of carburetor components.
    • 6 Look for abnormal wearing on the jets, float valve, gaskets, O-rings and springs. If you have not changed altitude or modified your bike in any way, then it is best to inspect these components. Any one of these components, or a combination, may be contributing to your starting issues. You may choose to replace individual parts such as a new float valve, though replacing all the interior components with a carburetor "rebuild kit" is advised. Rebuild kits can be ordered online or through your dealer, and will ensure your carburetor is fully repaired.
    • 7 Slide the gasket, spring, spring holder and needle jet assembly back onto the carburetor cap and insert the assembly into the top of the carburetor. Screw the main jet into the bottom of the needle jet assembly by accessing it through the bowl area. Screw the pilot jet back into its hole below the main jet. Clip the float valve onto its hinge within the bowl a insert the bowl gasket. Screw the bowl to the bottom of the carburetor to complete the re-assembly process.
    • 8 Re-attach the carburetor to the intake manifold using the hose clamp and screwdriver. Slide the fuel feeder line onto the brass receiver port on the side of the carburetor and slide the air box boot over the carburetor's intake port, which should be facing toward the back of the bike. Re-install the air filter with its wing nut, slide the clips over the air box top to secure it to the box and slide the seat into place. Re-install the seat screws to complete the re-assembly process.
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1 Answer

2001 raptor 660r with k&n air filter and full Yoshimura exhaust I need to know the settings for the carburetor jets, needles, and pilot jets


will need to fit larger pilot and main jet
size will depend where you are as colder climate will need to be richer than warm climate, normally 1 size up from std on pilot and 2 on main

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