Caburetor synchornization on the Kawasaki Ninja EX-250 must be checked and adjusted every 3,000 miles. Under hard riding conditions, you may need to check and adjust the caburetors more often.
It should take about 1 hour depending on how familiar you are with checking and adjusting carburators and the bike in general.
If done improperly, damage to your engine may result. If you feel at all uncomfortable with this process we suggest having a qualified technician perform the carburetor synchronization.
References to "left side" and "right side" are from the point of view of the rider sitting on the bike. For example, the throttle would be on the right side of the bike.
"One whole turn" of a screw or bolt is a 180° turn of the screwdriver or wrench.
The following symbols may appear when a tool is required. Refer to the "Tools Required" section below for a list of tools that are required.
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Tools |
Instructions |
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| 1. |
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Place bike on center stand: With the bike on the side stand, grasp the left handle bar with your left hand and the sissy bar with your right. Place your right foot on the center stand foot peg that sticks out just below left muffler. Press down with your foot until the stand hits the ground. Rock the bike left and right while applying some pressure to the center stand with your foot until it feels like the bike is on both posts. Press down with your foot at the same time as you pull towards the rear of the bike with your left hand and pull up with your right hand until the bike rests completely on the center stand. |
| 2. |
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Remove the seat: Unlock the seat with the lock embedded in the rear fairing. It is located on the left side. Pull up and back on the rear end of the seat. |
| 3. |
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Remove side fairings: Remove the screw on the side fairing with the #2 Phillips head screwdriver. Gently pull the rear of the side fairing straight out until the rear pops out. Gently bottom of the rear fairing straight out until it pops out. The fairing should now come away. Repeat for the second side fairing. |
| 4. |
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Remove bottom fairing: Remove the bolts on the rear of the bottom fairing. Remove the four bolts that attach the front fairing to the bottom fairing with the #2 Phillips head screwdriver. Remove the bolt in the center of the front of the bottom fairing. Be sure to hold bottom fairing as you remove the last bolt as it may fall off. |
| 5. |
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Remove front fairing: Remove the rubber plug and bolt on each mirror with the 6mm Allen wrench. Remove the four bolts that attach the front fairing to the gas tank with the 4mm Allen wrench. Disconnect the two wires connecting each turn signal inside the front fairing taking not of the polarity of the wires. Pull the front fairing straight out and set aside. |
| 6. |
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Warm up engine: Turn the engine on and let it warm up completely. |
| 7. |
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Adjust idle speed: Adjust the idle speed by turning the adjustment screw on the carburetor located just below your petcock. The idle speed should be between 1200 and 1400 RPMs (1300 and 1500 RPM in CA). |
| 8. |
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Shut off the engine |
| 9. |
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Turn off fuel: Turn the petcock (fuel switch) located on the left side of the bike just below where the gas tank, front fairing, and side fairing come together clockwise until it point to the "off" position (towards the rear of the bike). |
| 10. |
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Remove fuel tank: It is not necessary to have a mostly empty fuel tank before removing it. Remove the two bolts at the rear of the tank. Disconnect the overflow line (located next to the bolts at the rear of the tank) using the needle nosed pliers to gently loosen and slide the hose clamp down and then pull gently on the hose. Disconnect the fuel line using the needle nosed pliers to gently loosen and slide the hose clamp down and then pull gently on the hose. There will be fuel in your fuel line so be ready with a towel to soak it up when you disconnect the line. Disconnect the vacuum actuator line using the needle nosed pliers to gently loosen and slide the hose clamp down and then pull gently on the hose. Set aside the fuel tank taking care not to damage your petcock when setting your tank down (A pair of 2x4s or an empty desk drawer can be used as a support).
 WARNING: Do not place the fuel tank on the petcock. Doing so may damage your fuel tank. |
| 11. |
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Remove carburetor vacuum hoses: Remove the two carburetor vacuum hoses from vacuum connectors on the carburetor intake manifold using the needle nosed pliers to gently loosen and slide the hose clamp down and then pull gently on the hose. |
| 12. |
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Attach the carburetor sync tool hoses: Attach the carburetor sync tool hoses for carburetor one and two to the vacuum connectors on the carburetor intake manifold. |
| 13. |
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Disconnect the breather hose: Disconnect the breather hose on the carburetor sync tool. |
| 14. |
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Turn on the engine |
| 15. |
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Adjust the carburetors: Adjust the carburetors using the adjustment screw (located between the two hoses) until there is less then a 2cm difference between the two mercury levels. You have a limited amount of fuel left in the lines so you need to do this as quickly as possible.
WARNING: Be careful when revving your engine to not let the mercury get sucked into the carburetors. |
| 16. |
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Reconnect the breather hose: Reconnect the breather hose on the carburetor sync tool. |
| 17. |
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Disconnect the carburetor sync tool: Disconnect the carburetor sync tool hoses from carburetor by removing both hoses. Reattach the carburetor sync tool hoses to the carburetor sync tool. |
| 18. |
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Reattach vacuum hoses: Reattach the two hoses to the vacuum connectors on the carburetor intake manifold. Secure the hoses using the hose clamps using the needle nosed pliers. |
| 19. |
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Install the fuel tank: Set the fuel tank on the two rubber mounts connected to your chassis. Attach both bolts using the 10mm socket wrench. Reattach the overflow line and secure it with the hose clamp using the needle nosed pliers. Reattach the fuel line to the petcock and secure it with the hose clamp using the needle nosed pliers. Reattach the vacuum actuator line to the petcock and secure it with the hose clamp using the needle nosed pliers. |
| 20. |
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Install bottom fairing: Reconnect the bottom fairing and tighten the 3 bolts using the #2 Phillips head screw driver. |
| 21. |
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Install front fairing: There are two pegs below and to the side of your headlight that fit into two rubber washers in the front fairing that act as a guide. Attach both mirrors using the 6mm Allen wrench. Connect the front fairing to the gas tank with 4 bolts using the 4mm Allen wrench. Attach the front fairing to the bottom fairing with 4 bolts using the #2 Phillips screwdriver. Replace the rubber plugs in the mirrors. Reconnect the left and right turn signals taking care to verify that the polarity of the wires is correct. |
| 22. |
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Install side fairings: Gently push the rear pegs of the side fairing into the rubber mounts. Gently push the front peg of the side fairing into the rubber mount at the same time inserting the plastic hook under the gas tank. Secure the side fairing with one bolt using the #2 Phillips screwdriver. Repeat for the other side fairing. |
| 23. |
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Install seat: Insert the tab on the bottom front of the seat into the slot just behind the gas tank. Press gently on the rear of the seat until it latches in place. |
| 24. |
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Turn on fuel: Turn the petcock located on the left side of the bike just below where the gas tank, front fairing, and side fairing come together clockwise until it point to the "on" position (towards the ground). |
| 25. |
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Conduct pre-ride inspection: Conduct your normal pre-ride inspection also taking note that all fasteners are tightened and no parts are left over. |
| 26. |
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Test ride the motorcycle listening for any anomalies: As you ride the bike, you may need to adjust the idle speed by turning the adjustment screw on the carburetor located just below your petcock. |
This guide is intended to demonstrate the procedure for checking and synchronizing your carburetors. Always consult your service manual before doing any maintenance or repair on your bike or have your carburetors checked and synchronized by a qualified technician. The authors and ForceOne Technologies, Inc. are not liable for any damage to the bike, property, riders, or passengers as a result of the use or misuse of this guide.
This guide was created by William "ForceOne" Pantoja with the help of Allie "Drain Fade" Daneman.
