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 one or two of which we provide with any given tool kit. In addition, many 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. If our socket doesn't fit, 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!
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 only a 5/8" hex plug, our newer RoadTech kits provide only 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 a 18mm hex, requiring use of a different socket. First, a little editorial about so-called "high-performance" plugs - unless you've 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 simply use a deep-well 11/16" or 18mm 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 some kits, which might seem odd for a metric vehicle. However, these are common spark plug hex sizes on many plugs for metric vehicles. Note that 5/8" equals 16mm, and is the most universal size on Powersports vehicles. The other size typically encountered is 18mm, which we include in our SPEEDKIT JAS, EU, and DMX as a combo 5/8" x 18mm socket.
If you have trouble getting the OEM 18mm socket, a standard deep-well socket may work on a bike with easily accessed plugs.