We endeavor to provide spark plug sockets that will work on your vehicle, but in some applications the CruzTOOLS-supplied socket(s) won't fit. As noted below, there are three principal hex sizes in use; only two of which we provide. In addition, many newer vehicles require a special thin-wall socket to fit into the head, and at a specific length in order to clear the tank and/or frame. In these cases, you may need to acquire the OEM spark plug socket for your specific make and model.
This may be somewhat moot, however. With the proliferation of fuel injection and electronic ignition, spark plugs seldom foul or fail, thus limiting removal to regular service intervals. That's a good thing, because many bikes require removal of bodywork, tank, and even radiator to gain access to spark plugs!
For Harley-Davidsons
Our EconoKITs for Harley-Davidsons include both 5/8" and 13/16" socket sizes, which will cover Sportster®, EVO®, and Twin-Cam® motors. Since all models after 1999 use a 5/8" hex plug, our newer RoadTech kits only provide one socket. If you need a 13/16" socket, let us know and we'll swap it out for the 5/8" size.
Some aftermarket plugs have an 18mm hex, requiring the use of a different socket. First, a little editorial about so-called "high-performance" plugs - unless you have had major work on your motor, expensive plugs won't provide any benefit and therefore don't justify the extra cost. If you do go this route and need the 18mm socket, you can obtain one inexpensively from Sears (part number 0943330), or simply use a deep-well 11/16" socket.
On the EconoKIT H1 and both RoadTech kits, use the supplied adjustable wrench as breaker bar for the spark plug socket.
For Metric Vehicles
We provide a 5/8" x 13/16" socket with most kits, which might seem odd for a metric vehicle. However, these are common spark plug hex sizes on many plugs for metric vehicles. The other size typically encountered is 18mm, which we don't include in any kit. That's primarily because most vehicles using 18mm require a special socket as described above.
If you have trouble getting the OEM 18mm socket, try one for a four-stroke dirt bike since many are this size. It may involve a little trial and error, but if you have a cooperative dealer the correct socket might be found. Bikes with easily accessed plugs, like BMW Boxers and Gold Wings, can often use a standard forged 18mm socket such as the one offered by Sears (part number 0943330).