Kawasaki Ninja EX250J8F Valve Clearance Adjustment Procedure Guide
Kawasaki Ninja EX250J8F Valve Clearance Adjustment Procedure Guide
Introduction
The valve clearance adjustment procedure for the EX250J8F is not for the faint of heart. It is time consuming and organization is very important. Precision and preplanning are critical. This guide is meant to be a supplement to the Kawasaki 2008 Ninja 250R (EX250J8F) Motorcycle Service Manual and not in any way is a substitute for the factory manual.
A discussion of why one would want to grapple with a project as complex as this is applicable. First, doing it yourself will assure the that the valve clearances are within specification. Second, you can take the time to measure the shims and set the clearance as consistently as possible between the valves. Third, you can keep track of how the valves are wearing (settling) from clearance check to clearance check. And fourth, most dealers do not stock shims so the procedure is likely going to require a week or better of down-time; do you honestly want your motorcycle piled in various locations around a shop getting moved, knocked over, stepped on, and such for a week?
Securing the shims turned out to be quite the challenge. I spent an inordinate amount of time trying to locate, order, and purchase the correct shims. Two situations were major contributors to this time delay.
First and foremost, no local dealers stock shims at all in 7.48 mm sizes and many just don't stock shims of any size. This is surprising as most quads and dirt bike also use shims so the service market is not limited to sport bikes. When I inquired about the number of valve jobs done on sport bikes the comments from two service departments was "they don't come in". They are often wrecked or sold before the first valve clearance check. Dealers are partly to blame for this because shims are not kept in stock. Most sport bike owners are unwilling to shell out $200 or more for a week of down time. Another large group of owners just are not aware of how important the valve clearance is to the longevity of high performance engines. There an awful lot of sport bikes running around out there with "tight" valve clearance. It would seem that if one purchases a used sport bike the first thing that should be done is a valve clearance check.
The other major issue was that Kawasaki USA doesn't import the 0.025 mm increment shims even though they mention them with part numbers in the service guide. A call to Kawasaki confirmed this. This situation has the effect of forcing one to look to the after market for shims that will allow fine tuning of valve clearances.
The first contact was to Sherman Power Sports to speak with parts and service to locate the shims I needed to set the valve clearance. It was from the parts staff at Sherman Power Sports that I found out that Kawasaki set the list price of the shims at $13.99 a shim! Fortunately they did have a 7.48 mm by 2.775 mm shim in their service department which they let me have as a trade for one of my shims.
Alba Action Sports of the San Diego area has developed a much needed valve shim exchange program for those that prefer their bikes to stay out of the local shop and safe at home in the garage thus avoiding potential damage by under-paid, ham-fisted technicians. Alba technicians actually took the time to measure shims and assure that I got as close to the 0.025 mm increment shims needed. Alba Action Sports was able to secure the shims and exchange them for mine at a reasonable price with a decent turnaround time. I recommend the Alba Action Sports Shim Exchange Program because it is a unique mechanism for the motorcycle enthusiast offered at a fair price and augmented with excellent customer service.
Having a shim kit at the house also turned out to be a necessity when attempting this procedure as having a variety of shims to choose from in order to fine tune the clearances. Shims of a particular size (thickness) will vary a bit on either side of the size stamped on the shim. Jentsch Racing of Queen Creek, Arizona offers to have good pricing and excellent service on Hot Cams kits and refills. Jentsch Racing was able to ship a Hot Cams 7.48 mm (2.70-2.95 mm) shim refill kit to me in short order so I could have a wide variety of shims to measure and choose from.
Tips
Keep the various fasteners from each component in a "baggie" that is clearly labeled (I slipped "Post-It" notes inside the baggie). You will use a lot of baggies.
Have the proper tools necessary for the successful completion of this procedure. In addition to a good set of mechanics tools you must have the following:
Reassemble according to factory torque specifications found in the Kawasaki 2008 Ninja 250R (EX250J8F) Motorcycle Service Manual.
Purchase a Hot Cams 7.48 mm valve shim kit (I purchased a 2.70-2.95 7.48 mm shim refill kit). I found Jentsch Racing (25706 South 182nd., Queen Creek, Arizona) to have good pricing and excellent service on Hot Cams kits and refills. Use the Alba Action Sports Shim Exchange Program to get the 0.025 and 0.075 mm increments as Hot Cams and Kawasaki USA offer only 0.05 and 0.1 mm increments. Keep your local motorcycle dealers in mind as they may just have a shim or tow in the size you need.
Above all, take your time and double check each step. Allow about a week to two weeks to complete the procedure.
Instructions
Place the Ninjette II on stands to assure the bike remains stationary and upright.
Remove the seat and knee pads.
Remove the left and right lower fairing halves (there are several plastic rivets of two different sizes you want to familiarize yourself with).
Remove the fuel tank.
Drain the coolant into a bucket by disconnecting the lower radiator hose (remember to dispose of the coolant safely).
Remove the clutch cable.
Remove the coolant reserve tank.
Remove Stebel Nautilus air horn if so equipped.
Remove the thermostat housing (take note of the location of the ground wires) and associated hoses. There will be some coolant loss during this procedure so be prepared.
Remove the coolant reserve tank upper bracket.
Disconnect the primary and ground leads from the right (#2) ignition coil.
Remove the left and right spark plug caps.
Remove the upper and lower right side radiator bracket mounting bolts.
Remove the right engine mount bracket: the two upper mounting bolts need to completely removed. The long 14 mm bolt will need to have the associated nut removed and the bolt gently driven far enough into the cylinder block mounting tube so the bracket can be lowered. Care should be taken to assure the other end of the 14 mm bolt clears the lower radiator hose on the left side of the engine.
Disconnect the air suction valve (crank case ventilation) hose.
Remove the inspection plugs on the alternator cover with a half-dollar, similar diameter large washer, or some silly "fake" coin you've picked up somewhere in your travels.
"Fake" coin tool.
Remove the cylinder head cover (This is takes more maneuvering than it looks like it should because of a little tab on the valve cover that keeps the rear vent pipe in place. Be patient and careful).
Tab and rear vent pipe.
Use a 3/8" break-over handle or 3/8" ratchet handle and 14 mm deep well socket to rotate the crank shaft to position the cam lobes over the valve lifters. Rotate the crank shaft counter clockwise and check valve clearance when piston is at top dead center and cam lobes are pointing away from the valve and each other as indicated by the service manual.
I have both a metric and English feeler gauge and using a combination of the two could measure the following increments which encompass the range specified by Kawasaki: .10 mm, .102 mm, .127 mm, .15 mm, .152 mm, .15 mm, .172 mm, .20 mm, .203 mm, .229 mm, .25 mm, .254 mm, .278 mm, and .30 mm.
Use the Ninja EX250J Valve Clearance Adjustment Excel Spread Sheet to keep track of the valve clearances.
The Kawasaki service manual mentions that there is a “2|T” mark (#2 piston at Top Dead Center) visible through the upper alternator inspection plug. There was not such a mark on my Ninjette II. There was however a white paint mark on the flywheel where the a “2|T” mark should have been (see the blurred photo above -- that is not a "flash" highlight it is a white paint mark).
The Kawasaki service manual mentions that there is a “2|T” mark (#2 piston at Top Dead Center) visible through the upper alternator inspection plug. There was not such a mark on my Ninjette II. There were also several other white paint marks. Two paint marks as described by the Kawasaki service manual indicate the proper alignment of the camshaft sprockets. There were additionally paint marks on the cam chain and the upper cam chain guide. It may take several revolutions but get all the marks lined up -- the “2|T” mark with the engine case, the two camshaft sprockets marks facing each other, and the cam chain mark with the upper cam chain guide mark (see photograph). When reinstalling this will allow an alignment double check at multiple points to be sure everything is correctly refitted.
Remove the camshaft chain tensioner by first loosening the 10 mm tensioner cap bolt and then the removing 8 mm cam chain tensioner mounting bolts by gradually loosening each bolt a little at a time taking care the tensioner housing doesn't’t get cocked due to push rod spring pressure.
Remove the cam shaft caps by gradually loosening each bolt in a cross-hatch pattern as there will be some valve spring tension exerted on the cam shaft. Be careful to keep the cam shaft’s position in the cam shaft cap bearings as even as possible. Use a 3/8 inch drive ratchet handle with an 8 mm socket due to the torque requirements of these little bolts.
Carefully lift and remove each cam shaft cap taking care that the six (four outer and 2 inner) dowel pins (which are short little tubes) remain in the cylinder head. Take great care to assure the caps remain even with the cylinder head during the process.
Remove each cam shaft by lifting and moving each cam shaft toward engine center. After removing the cam shafts double check to be sure the crankshaft is still on the “2|T” mark (#2 piston at Top Dead Center). Use a clean rag to keep the cam chain from dropping into the engine case.
Carefully remove each valve lifter. The shim will most likely stay with the valve lifter.
Top of valve stem showing the "seat" where the adjustment shim resides.
Use a micrometer to measure the existing shims and the Ninja EX250J Valve Clearance Adjustment Excel Spread Sheet to keep take of the measurements. Use the Ninja EX250J Valve Clearance Adjustment Organization Sheet to keep track of the location of the valve lifters (buckets) and shims in the engine.
Detail of Ninja EX250J Valve Clearance Adjustment Organization Sheet and the "mini" muffin pan used to keep lifters and shims in while waiting for the "new" shims to gathered .
To keep the engine clean replace the alternator cover inspection plugs and place the cam shaft cover on the engine head. Cover the engine with a clean towel.
Box of parts (note the labeled baggies).
There are often subtle differences in the individual thickness of each of the "replacement" shims. You can exploit these differences by measuring each shim and arranging the respective shims to gain as even a valve clearance between the individual valves as possible. The Ninja EX250J Valve Clearance Adjustment Excel Spread Sheet is designed to help you with this objective. (This is what my First EX250J Valve Clearance Adjustment looked like. I was aiming toward the upper end of the factory tolerances in hopes that the next inspection would show the valves should still be in specification.)
Coat each shim with molybdenum disulfide grease and place each one on their respective valve spring retainer.
Coat each valve lifter with molybdenum disulfide grease and place it over its respective shim and valve.
Assure that the crankshaft is still on the “2|T” mark (#2 piston at Top Dead Center) in the alternator cover inspection port. Coat the camshaft journal bearings of the engine head with molybdenum disulfide grease then coat the journals and cams of the exhaust camshaft with molybdenum disulfide grease. Pull the forward section (exhaust side) of the cam chain taught and place the exhaust camshaft in it's bearing journals.
Coat the journals and cams of the intake camshaft with molybdenum disulfide grease. Pull the cam chain taught from the exhaust sprocket and work it on the intake camshaft sprocket so the intake cam shaft will settle in it's journal bearings. Assure that everything is lined up according to the Kawasaki Service Manual
Coat the journal bearings of the camshaft caps with molybdenum disulfide grease. Place the camshaft caps on the each respective camshaft in accordance with Kawasaki specifications.
Use a "crossing" pattern to very gradually settle and seat the camshaft caps on the engine head. Remember the engine head and camshaft caps are aluminum and the camshafts are a cast steel alloy -- damage can occur to the journal bearings if care is not taken.
Once the camshaft caps are fully seated gradually torque the camshaft cap bolts following the sequence numbers molded on the camshaft caps in accordance with the Kawasaki torque specifications outlined in the service manual.
The EX250J8F has a non-return type camshaft chain tensioner. Refitting this little jewel must be done with care. Above is a picture with the chain tensioner push rod fully extended.
A couple of suitable tools are needed for retracting the chain tensioner push rod: 1) a 15 year old Craftsman blade screwdriver (with the handle shortened to clear the air box -- Milwaukee Sawzalls rock) has a blade width that will keep the camshaft chain tensioner push rod retracted during the install and 2) a small blade screw driver that fully enter the camshaft chain tensioner housing and retract the push rod.
Reset the camshaft chain tensioner push rod by compressing the push rod back into the tensioner housing while rotating the push rod clockwise with a small screwdriver. (Photo by Victoria Yeager)
Hold the camshaft chain tensioner push rod in place with the modified screwdriver.
Note the blue dot and the number "2" (washed out in photo) on the camshaft chain tensioner housing. These go toward the centerline of the engine (not facing outward).
The camshaft chain tensioner push rod pressure pad should be oriented up and down. Place a bit of molybdenum disulfide grease on the pad.
Carefully seat the camshaft chain tensioner with a new gasket.
Remove the the modified screwdriver. Carefully torque the camshaft chain tensioner mounting bolts and chain tensioner cap bolt to Kawasaki specifications.
Double check the valve timing turning the engine counter clockwise and assuring all the "timing marks" line up as before.
Double check the valve clearance. I used a 0.009" inch and a 0.30 mm as a "go" / "no-go" test on the exhaust and a 0.15 mm and a 0.25 mm as a "go" / "no-go" test on the intake. (The double check indicated that the First EX250J Valve Clearance Adjustment resulted in clearances that were consistently just in the upper end of the factory tolerances.)
Remove the seals for the sparkplug ports from the cylinder head cover and reseat them on the cylinder head.
Double check the camshaft cap bolt torque.
Torque the cylinder head cover mounting bolts to Kawasaki specifications.
The re-assembly procedure is complicated enough that I felt compelled to list the steps below:
Connect the air suction valve (crank case ventilation) hose.
Refit the right engine mount bracket and torque the mounting bolts to Kawasaki specifications.
Connect the primary and ground leads from the right (#2) ignition coil.
Refit the upper and lower right side radiator bracket mounting bolts to Kawasaki specifications.
Refit the left and right spark plug caps.
Refit the coolant reserve tank upper bracket.
Refit the thermostat housing.
Refit the coolant reserve tank.
Refit clutch cable.
Top up the engine coolant.
Refit Stebel Nautilus air horn if so equipped.
Refit the fuel tank, connect fuel and vacuum hoses, but do not attach it at the rear.
Elevate the rear of the tank to provide space to get your hand and a small Phillips screw driver between the carburetors and the engine. (The tank does not need to be removed as with earlier models. The remainder of the procedure is identical to earlier Ninja 250R models).
Connect the carburetor synchronizer.
Pray.
Start the engine and bring it to normal operating temperature.
Synchronize the carburetors. Carburetor synchronization details are discussed on a variety of websites and in the Kawasaki Service Manual and will not be further discussed here.
The clearance between the carburetors is very tight filled with all manner of vacuum lines, fuel lines, and cables. This screw driver bit turned out to be just the right size.
Refit fuel tank fully.
Change the motor oil and filter.
Refit the left and right lower fairing halves.
Refit the seat and knee pads.
Clean and wax the motorcycle.
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