Motorcycle Repair: kawasaki NINJA ex250 CDI BOX, kawasaki ninja ex250, timing curve

Question
QUESTION: Hi I have a question I have a 99 kawasaki ninja EX250-F-13 with a NINJA EX250-F-12 MOTOR in the bike MY Problem is the CDI for the 99 motor is still on the bike I dont have a clue on how to cross ref the TO CDI BOXES TO SEE IF THE 99 CDI would work for the 98 MOTOR COULD YOU HELP ME THANKS I AM ABOUT TO JUNK THE BIKE IF ANYTHING I AM SO TIRED OF NOT BEING ABLE TO RIDE

ANSWER: Jason,Im not sure can you check the vin# on the bikes and it may have on the number sequence if its a California unit. The outside appearance of the CDI may look the same its the Timing curve and spark advance that will mess with you. Sometimes there are numbers video jet inked on the outside of the igniter box but I think its Kawasaki's warehouse location numbers and not a part number. The other thing is the trigger coil by the flywheel can be bad also giving you the back fire you may be experiencing.

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QUESTION: I dont have the 98 ninja just the motor  and I will check and let you know and the trigger coil what is that the motor has been totally rebuilt from my understanding  I just had to put my old starter motor IN the motor and put the motor in my bike

ANSWER: Jason,The trigger coil is a small block shaped electrcal device that tells the coil when to fire. Its set in the side cover next to the flywheel and the flywheel has a raised spot on the outside of it and as it passes by the trigger coil it has about .010" clearance and interferes with the magnetic flow and pulses the electronic signal and the coil fires in short. Is there any way you can call the place where you got the motor and they might be able to tell you if the bike was a Cal. model or at least guarantee it was a running unit and wasn't salvaged out due to something going wrong with the rebuild,they may not tell you for fear of loss of a sale.

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QUESTION: NO I cant call the place because I bought it from a guy off Ebay could maladjusted valves be to blame for the backfiring and low compression because the coils fire but the bike just backfires out the tailpipes I am going to pull the motor again and check and another thing I was checking the timing marks on the crank and didnt see them how can I tell if the timing is set right without them I guess I am going to just wait and see when I pull the motor again I will reply when I do to let you know what if anything I find wrong thanks for the help

Answer
Lets assume the CDI is correct,I dont remember any comment on low compression but here goes.Pull the valve cover off and pull the two plugs out of the left side cover. Take a socket and put on the bolt in the flywheel and turn the engine over. Go ahead and pull the sparkplugs out it will be easier to turn.Watch the intake side and the lobes on the cam will point away from the valve. As the piston comes up to TDC the timing mark may appear in the smaller plug hole by the flywheel. Also take a piece of wire or stiff zip tie or a long but small diameter and poke down through the spark plug hole and feel for the top of the piston. You should be able to feel the top of the piston as you bring it to the top,if you go to far the piston will start to drop.The TDC mark should be in the window now. Take a feeler gauge and check the clearance between cam and shim bucket the intake side should have no less than .004" and the exhaust side should have no less than .006". If these don't come in and are to tight then the shims under the buckets will need to be replaced with the proper clearance. Otherwise the backfiring and hard starting will occur.The shims have numbers etched onto them but if they are worn off then they will need to be measured with a caliper and drop down to a workable size that will give you the clearance you need. As far as timing that doesnt change unless someone has gone in and physically changed something.