Intake and exhaust valves on the Kawasaki Ninja EX-250 must be checked and adjusted every 6,000 miles. Under hard riding conditions, you may need to check and adjust the valves every 3,000 miles. Your carburetors must be synchronized and your spark plugs must be cleaned and gapped every 3,000 miles. Coolant needs to be flushed every 2 years or every 18,000 miles whichever comes first but under hard riding conditions you may need to flush it more often.

There is a certain technique to valve adjustments that will yield the best performance or best longevity from the Ninja's quarter-liter engine. Simply put, using a slightly tighter adjustment will generally yield greater horsepower but will negatively impact longevity. Inversely, a slightly looser adjustment will yield greater longevity while negatively impacting maximum horsepower. However, according to Kawasaki, using the median of the recommended valve adjustment valves will provide the greatest balance of longevity and horsepower.

It should take about 2 to 3 hours depending on how familiar you are with adjusting the valves and the bike in general.

A short version of this guide is available.

WARNING

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You are about to get into the deepest parts of your engine and perform the most difficult maintence task for your bike. If done inproperly, damage to your engine may result. If you feel at all uncomfortable with this process we suggest having a qualified technician perform the valve adjustment.

• Read through all the instructions carefully before starting.
   
• Make sure you have the appropriate tools before you start.
   
• Your engine must be cold before performing a valve check and adjustment. Let your bike sit for at least 6 hours prior disassembly.

Guide Conventions

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Warning symbols appear when you need to pay special attention or damage to you or the bike may result.

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.

Optional Tasks

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• Replace the spark plugs: You may choose to replace the spark plugs if they are worn or damaged.
   
• Replace valve cover gasket: Because you will already have the valve cover off, you may wish to replace the valve cover gasket if it needs it.
   
• Remove the ignition coil brackets: It is not necessary to remove the ignition col brackets but you will find that you have more room if you do so.
   
• Remove the radiator: It is not necessary to un-bolt the radiator to adjust the valves but you will find that you have more room if you do so.
   
• Drain the coolant: It is not necessary to drain the coolant. If you do, will be able to disconnect the radiator hoses and be able to pull the radiator farther away from its mountings.
   
• Replace the coolant: It is not necessary to replace the coolant each time you adjust the valves. Coolant needs to be replaced once every 2 years or every 18,000 miles whichever comes first. You can save the coolant drained from the radiator and reuse it.

Tools Required

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	Tool
	Needle nosed pliers
	3/8" Slotted screwdriver
	1/8" Slotted screwdriver
	#2 Phillips screwdriver
	4mm Allen wrench
	6mm Allen wrench
	Socket wrench
	10mm socket
	14mm socket
	Torque wrench covering 69 in-lbs to 87 in-lbs
	Shop towels
	[Optional ] Power drill
	[Optional ] 1/4" Titanium drill bit
	Container for coolant (1L clean plastic bottle or other suitable container)
	Supports for fuel tank (a couple of 2x4s or a desk drawer)
	SPECIAL TOOL: Kawasaki Valve Feeler Gauge tool #57001-1221 (assorted feeler gauges between 0.08mm to 0.16mm may be used instead)
	SPECIAL TOOL: Kawasaki Valve Adjustment tool #57001-1220 (a suitable socket with extension and slotted screw driver may be used instead)
	SPECIAL TOOL: Push-pull or force guage (locknuts may be tightened by hand if one is not available)
	SPECIAL TOOL: Carburetor Synchronication tool (We used the Motion Pro Carburetor Synchronication Tool) WARNING: Mercury is a toxic material. If you spill any mercury, follow the regulations in your state for clean up and disposal.
	Kawasaki Ninja EX250 Service Manual and addendum.

Parts

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• [Optional ] 6" zip tie or a length of string or wire
   
• [Optional ] Coolant
   
• [Optional ] Distilled water
   
• [Optional ] NGK CR8HSA or ND U24FSR-U Spark Plugs (For cold weather and/or low speed riding, you may use NGK CR7HSA or ND U22FSR-U spark plugs)
  
  WARNING: Do not use NGK CR7HSA or ND U22FSR-U spark plugs for normal temperatures and/or high speed riding as engine damage may result.
   
• [Optional ] Valve cover gasket

Disassembly

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	Tools	Instructions
1.		Let the engine cool: Your engine must be cold before you can check and adjust the valves. Let your bike sit without starting the engine for at least 6 hours.
2.		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.
3.		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).
4.		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.
5.		Disconnect the negative lead on the battery cable: Loosen the bolt holding the wire and remove the negative lead with the #2 Phillips head screwdriver.
6.		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.
7.		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.
8.		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.
9.		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.
10.		[Optional ] Drain coolant: Open radiator fill cap and drain your coolant by removing the water pump drain plug. If you plan on re-using your coolant, save it in a clean container. You may skip this step if you do not wish to drain your coolant. However, you will not be able to pull the radiator away as far. WARNING: Coolant is a toxic material and can be harmful or fatal to humans and pets.
11.		[Optional ] Replace the water pump drain plug: If you drained your coolant, replace the water pump drain plug using a torque wrench set to 69 in-lbs of torque.
12.		Remove spark plug ignition coils: Remove the spark plug ignition coils by removing the two bolts and disconnecting both wires. Take note of where the wires are connected to the ignition coils. Repeat for the second spark plug ignition coil.
13.		[Optional ] Drill out the spot weld: Using the 1/4" titanium drill bit, drill out the spot weld holding the ignition coil bracket to the chassis. Repeat for the other ignition coil bracket. WARNING: Always wear eye protection when using power tools. Damage to eyes may result from metal shavings.
14.		[Optional ] Remove the ignition coil brackets: If the spot weld that holds the ignition coil brackets in place has been drilled out, remove both bolts holding the ignition coil bracket. Repeat for the other ignition coil bracket.
15.		Remove spark plug wires: Grasping the wires at the base where they meet the valve cover, pull up gently on the spark plug wire. Repeat with the other spark plug wire.
16.		[Optional ] Disconnect radiator hoses: Only if you drained your coolant, loosen the hose clamps on the radiator side from the two radiator hoses and disconnect them from the radiator.
17.		[Optional ] Secure the radiator: Using a zip tie, secure your radiator to your front forks. This will keep it suspended when you remove its bolts but avoid having to remove it completely.
18.		[Optional ] Disconnect the radiator: Remove the 4 radiator bolts and pull the radiator gently away from the engine. It should hang supported from the zip tie.
19.		Remove the timing sight cover and the crank cover: Remove the timing sight cover and the crank cover with the 1/4" slotted screwdriver. Take care not to lose the o-rings on both of these covers. WARNING: Take care not to allow foriegn material to get inside the engine or on the parts removed.
20.		Remove value cover: Remove the four bolts holding the valve cover in place with a 10mm socket wrench. WARNING: Take care not to allow foriegn material to get inside the engine or on the parts removed.

Value Adjustment

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	Tools	Instructions
1.		Turn crank to TDC: Turn the crank using the 14mm socket counter-clockwise until the number one cylinder intake valves are at top dead center (TDC) using the 10mm socket. The lobes for the valves should be pointing up (the exact position of the lobes may vary from motorcycle to motorcycle) and the timing mark inside the timing sight should be centered in the mark on the crank.
2.		Check the clearance: Check the clearance of both intake valves (between 0.08mm and 0.13mm) using the feeler gauges.
3.		Adjust the valve clearance: If adjustment is required, use the Kawasaki valve adjustment tool to hold the adjustment screw in place whilst simultaneously loosening the locking nut or improvise a similar tool with a proper-fitting box wrench and screw driver. Then, once the locking nut is loosened approximately 1/4 turn, turn the adjustment screw to set the valve clearance to the proper gap. When clearance is set, hold the adjustment screw in place and tighten the locking nut to an appropriate torque. If you do not have a push-pull gauge to measure the force, you can tighten it by hand. The tightness should be "tight plus a smidge".
4.		Re-check the clearance: Re-check the clearance of both intake valves (between 0.08mm and 0.13mm) using the feeler gauges after you have tightened the locknut.
5.		Repeat for the remaining valves: Repeat the process for the number one cylinder exhaust valves (between 0.11mm and 0.16mm), the number two cylinder intake valves (between 0.08mm and 0.13mm), and the number two cylinder exhaust valves (between 0.11mm and 0.16mm).

Reassembly

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	Tools	Instructions
1.		[Optional ] Replace the valve cover gasket: If you choose to replace the valve cover gasket, do that now (refer to the service manual for instructions).
2.		Install the valve cover: Install the valve cover using a torque wrench set to 87 in-lbs of torque to tighten all 4 bolts.
3.		Remove spark plugs: Remove both spark plugs.
4.		Clean and gap the spark plugs: Clean the spark plug electrodes using a high flash-point solvent and a wire brush. Measure the gap between the electrodes with the feeler gauge (between 0.6mm and 0.7mm). Bend the outer electrode to adjust the gap.
5.		Install spark plugs: Install each spark plug using a torque wrench set to 10 in-lbs of torque.
6.		[Optional ] Reattach radiator: If you un-mounted the radiator, reattach the radiator using the 10mm socket. Reconnect the radiator hoses using the hose clamps. Remove the zip tie.
7.		Install the spark plug wires: Push the spark plug wires back into the engine gently until they snap in place.
8.		[Optional ]Install ignition coil brackets: If you removed the ignition coil brackets, install them now using the 10mm socket.
9.		Install the spark plug ignition coils: Install the spark plug ignition coils using the 10mm socket. Reattach the wires making sure the polarity of the wires is correct.
10.		Install the timing and crank covers: Install the timing and crank covers using the 3/8" slotted screwdriver. Be careful as you screw them in so you do not pinch the o-rings.
11.		[Optional ] Refill the radiator: If you drained your coolant, refill the radiator with coolant mixture of 50% coolant and 50% distilled water or use the coolant you saved. Leave the fill cover off. WARNING: You must used distilled (or soft) water and coolant safe for aluminum components.
12.		Install the fuel tank: Set the fuel tank on the two rubber mounts connected to your chassis. 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. You do not need to attach the overflow hose or the bolts.
13.		Reattach the battery: Attach the negative lead on the battery using the #2 Phillips screwdriver.
14.		Test fire the engine and listen for any anomalies

Carburetor Synchronization

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	Tools	Instructions
1.		Warm up engine: Turn the engine on and let it warm up completely.
2.		[Optional ] Add additional coolant: If you removed or changed your coolant, you may need to add additional coolant mixture as the engine warms up. WARNING: You must make sure all air bubbles are removed. Air bubbles trapped in your cooling system may cause it to overheat.
3.		[Optional ] Install radiator coolant fill cap: If you removed or changed your coolant, install the radiator coolant fill cap if you removed it.
4.		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).
5.		Shut off the engine
6.		Remove the fuel tank: 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. Trying to keep as much fuel in the fuel line as possible with spilling any. 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. WARNING: Do not place the fuel tank on the petcock. Doing so may damage your fuel tank.
7.		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.
8.		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.
9.		Disconnect the breather hose: Disconnect the breather hose on the carburetor sync tool.
10.		Turn on the engine
11.		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.
12.		Turn off the engine

Reassembly

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	Tools	Instructions
1.		Reconnect the breather hose: Reconnect the breather hose on the carburetor sync tool.
2.		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.
3.		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.
4.		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.
5.		Install bottom fairing: Reconnect the bottom fairing and tighten the 3 bolts using the #2 Phillips head screw driver.
6.		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.
7.		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.
8.		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.
9.		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).
10.		Conduct pre-ride inspection: Conduct your normal pre-ride inspection also taking note that all fasteners are tightened and no parts are left over.
11.		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.

Disclaimer

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This guide is intended to demonstrate the procedure for checking and adjusting valves. Always consult your service manual before doing any maintenance or repair on your bike or have your valves checked and adjusted 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.

Credits

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This guide was created by William "ForceOne" Pantoja with the help of Allie "Drain Fade" Daneman.