EX250F key blanks
If you need a new key for your bike, there are four flavors to choose from: good, hard-to-find, needs-tweaking, and expensive. A good locksmith should be able to tell which blank needs to be used, but some of them may not do much motorcycle business. This is to help you help them.
For a complete dissertation on the relationship between you and your vehicle keys, go to What do I need to know about keys?.
OEM Kawasaki key blanks
The OEM Kawasaki blank is part number 27008-1173. Dealers typically ask well over $10 for these. You can find them cheaper at places like Bike Bandit or Ron Ayers, but unless you're ordering other stuff at the same time, shipping charges make them the same or more than a dealer. The OEM key is nickel-plated brass (as are all the other keys mentioned here) with a plastic-coated head.
There is no functional reason to get an "official" Kawasaki key. If you like the plastic bit on the end that says Kawasaki, that's fine.
Ilco X103
The least expensive and most common key choice for the EX250F. This is also marked as KA14. Different in style but functionally equal to the OEM and Silca models.
The Ilco USA X103/KA14 is slightly shorter than the OEM key and is all-metal, with a head profile significantly different in shape. The length reduction is in the head end of the key. The portion of the key shaft that inserts into the lock cylinder measures the same as the OEM blank.
Note: There are two Ilco lines: Ilco USA and Ilco Italy (aka ORION). The Ilco Italy brand has a key marked KA14, but that key is not remotely related to any Ninja 250 key.
Silca KW12BP
The Silca KW12BP has a black plastic head like the OEM key. It is 3mm longer at the top but is functionally identical. Unless you held it against the OEM blank you wouldn't be able to tell the difference. The KW12BP is hard to find; you'll probably have to look for it online. Even then it will be hard to find. And it will cost about twice as much as the Ilco blank, though still less than the Kawasaki. Try My Security Pro.
Ilco X266
The Ilco X266 (also marked KA16) will work in the EX250, but it's really not the correct key. The proper blank (X103) is common enough. On the other hand, the modification required is easy for a locksmith to do, and if you have to choose between using an X266 and not getting a key made, you might want to go this route. Once the key is modified, it will work. It won't work at all in unmodified form. If you like, show this section of the FAQ to the locksmith for reference.
The X266 is not listed for the Ninja 250 but rather the Concours. This blank is also all-metal, but its shape is the same as the OEM key. The problem with the X266 is that there is a small ridge on each edge that prevents the key from being fully inserted into the Ninja 250 lock cylinders. The amount of interference is fairly small (less than a millimeter) but that is enough to cause problems. Without a minor modification to the key, an X266/KA16 blank cut to fit the ignition/seat/helmet locks will not work in the fuel filler cap.
Here's a closeup of the ridge in question:
You can see where the ridge interferes (seat lock cylinder shown):
The modification of the blank is to use a file or other tool to remove the ridge just at the end on each side. Only a small bit needs to be removed, although you can remove the whole ridge. It is critical to maintain the distance of 20mm from the tip of the key to the shoulder.
Before:
After:
Key dimensions
The critical dimensions of the three aftermarket blanks are identical to the OEM Kawasaki blank, with the exception of the ridges on the X266/KA16. The thickness and width of the part that inserts into the lock cylinder are the same. The most important dimension is the length from the tip of the key to the shoulder step (20mm). The reason for this is that the ignition, helmet, and seat lock cylinders rely on the shoulder stop to determine insertion depth, whereas the gas cap has an internal stop such that only the end five of the six tumbler positions are used. If that 20mm length were to change, then a key cut for the other three lock cylinders would not work for the gas cap, and vice versa.
