Pliers are multipurpose tools that let you apply great force at the tip due to leverage when you squeeze the handles. Pliers are considered a first-class lever. The longer the handles, the more leverage you have.
Quality of pliers is important. Cheaper versions will be manufactured from softer metals and will be more prone to damage when used on harder items. Again, this is dependent on the steel alloy and heat treatment used by the manufacturer. You might find a kit containing the four common types mentioned below. These will be used many times, so purchase the best ones you can afford.
There are a few styles that are useful for motorcycle maintenance.
Linesman’s (or Combination) pliers
Combination pliers earned their name due to their dual gripping and cutting capability. The “linesman” term refers to their extensive use by electrical linesmen. These pliers have serrated jaws at their stubby tip, and wire cutting jaws closer to the pivot.
They are most useful for a wide range of tasks where items need to be gripped very tightly. They will cut wire of some sizes, depending on the quality of the jaws, and the length of the handles (which determines how much leverage you can apply to the jaws).
Linesman’s pliers can be found in different sizes. They are typically measured from end to end. Smaller pliers around 7-inches (180 mm) long seem to work well. Larger ones can be too large to fit around motorcycles.
Needle nose pliers
Needle nose pliers also have dual gripping and cutting capability. However, on a motorcycle, they have the ability to reach into small spaces, which is handy, for example, when you have dropped a screw or nut in under the carburetors.
A couple of sizes are handy, one for general use, another smaller pair for hard to get to spaces.
Tongue-and-Groove pliers
Tongue-and-groove, “multi-grips”, or “Channel-lock” pliers, have an adjustable jaw that allows smaller or larger items to be gripped without affecting the handle opening, meaning you can maintain lots of leverage. Additionally, the jaws of the pliers generally remain parallel, which is helpful when gripping or clamping material. Handles are also quite long, which increases leverage and therefore gripping force at the jaws.
Good quality multi-grip pliers can be expensive. They are useful, but don’t need to be part of your initial toolkit if you can’t get them at a fair price.
Diagonal (Side Cutting) pliers
Diagonal pliers are generally intended for cutting wire. They are useful for electrical work on motorcycles, but also for cutting cotter pins (as used to secure axle nuts).
Circlip pliers
Circlips are a machine element that helps to retain parts in an assembly. They are a spring element that flexes during installation and removal. Once installed, they generally seat into a groove to prevent movement. Circlips are available in “internal” and “external” varieties.
Special pliers are used to remove and install circlips. They are spring loaded to suit either internal or external clips. The curved ends on some varieties help reach into recesses.
The circular tips in the pliers fit into the holes in the circlips.
The size of the circlips you are likely to find on a motorcycle would dictate the size of pliers you might need. If these are something that you don’t think you’ll use that often, you can often buy cheaper circlip pliers with interchangeable tips that allow them to work for both internal and external clips and often come with right angled tips.
Electrical pliers
For electrical work on your motorcycle, a variety of pliers will be useful. Let's look at each in more detail.
Multipurpose pliers
Multipurpose pliers are typically the first (and cheapest) electrical pliers you might add to your toolbox. Most have the following features:
- Wire cutters (a very rudimentary version)
- Crimping jaws for insulated terminals (more on these below)
- Shears for cutting small bolts
- Crimping jaws for non-insulated terminals
- Wire strippers for different cross section wires
Due to their variety of features and low cost, they are often included in cheaper tool and electrical kits. While they are “cheap and nasty”, they will be adequate to get started.
Wire stripping pliers
Once you have used decent wire strippers, you won’t want to go back to multipurpose pliers. They strip wire reliably and consistently. And like other quality tools, they will last a lifetime. If you need to wire an entire motorcycle, you’ll appreciate decent stripping pliers.
These pliers have an adjustable jaw to set the length of the stripped wire, a blade to cut the insulation, and cutters to trim wire to length.
Crimping pliers
Crimping pliers are needed to connect wires to terminals. Terminals allow wires to be connected and disconnected quickly. This is important in the factory to assemble the motorcycle, and in service to allow parts to be removed and installed for maintenance.
There are dozens of types of terminals, both those used on motorcycles, and those used in commercial, industrial or other automotive applications. Generally, crimping pliers need to match the types of terminals you’re using.
Generic insulated terminals are NOT suitable for motorcycles, even though they are cheap, available everywhere, and are easy to use.
Insulated terminals are simply squashed onto the wire. This type of connection is adequate when the wiring is stationary (for example, in an industrial switchboard). In an automotive application, where the wiring can vibrate and move around slightly, this type of terminal is prone to failures.
Terminals designed for automotive applications are a better choice. Examples are shown in the photo below.
If you crimp auto style terminals, you need a crimper that matches the terminals. The crimping pliers shown below are designed for specific terminals. While they are not cheap, they are the correct tool for the job.
For repairs or custom wiring jobs, it is worthwhile selecting the terminals you’ll use, then purchase a matching crimping pliers.