Smaller fasteners on motorcycles often have screw heads rather than wrench-driven hexagon heads. As the name suggests, you’ll need a set of screwdrivers to remove these types of fasteners. Ensure you have a screwdriver for each of the following screw heads.
The first mass-produced screw goes by many names, including flat blade, slot head, straight, flat, flat tip, and flat head. Whatever you call it, this screw head features one indented slot across it’s head. This slot accepts a flat blade screwdriver.
This screw head is becoming less common, as modern screw heads can be assembled quicker and tightened more accurately with automated assembly tools on production lines. However, you’ll likely come across a few when working on vintage bikes, so a a range of slotted screwdrivers will be useful.
Developed in the 1930s for auto manufacture, the most common screw head on motorcycles is the Phillips head screw. Instead of just one slot, it features a cross-shaped recess in the screw head. This design can cause the matching-shaped screwdriver to cam out or disengage from the fastener. Do this too many times and the screw head could become damaged so that a screwdriver is unable to find its grip.
Phillips head screws and screwdrivers are classified by a number size. Numbers #2 and #3 are often found on motorcycles. The matching screwdriver will likely be marked on the handle with the size. These screwdrivers are essential, and you will use them frequently. Typical sets will contain #0, #1, #2 and #3. The quality of the steel and heat treatment of the tip will determine how long these last. Purchase the best ones you can afford.
You might find some smaller screws in both slotted and Phillips head and a set of “jeweler's screwdrivers” might come in useful too.
You’ve probably heard of flat head and Phillips head screws before, but this next screw head design is far less common in the United States. In the late 1960’s Japanese equipment started appearing with a screw head that looked a lot like the Phillips – but was not. The Japanese local standards organization had released their standard Japanese Industrial Standard (JIS) B1012 “cross recesses for screws”. Sometimes there is a small dot stamped into the screw head to identify it is JIS, not Phillips.
While it is a cross-form screw, the dimensions of the recess are such that the driving tool is not designed to cam out. As a result, using Phillips screwdriver on a JIS B1012 screw might lead to screw damage.
It is important to find and use JIS screwdrivers on older Japanese motorcycles. However, you might struggle to find JIS screwdrivers on the rack in a local tool store. Save yourself the trip and search your favorite online marketplace instead.
Hexagonal head screws
On some fasteners you might find a hexagonal (six-sided) recess in the head of the screw. If you’ve used these fasteners, you might agree the chance of the tool slipping out of the head is much less with this design, and that is one of its major benefits.
To drive a hex-shaped recess you need a hex shaped tool. This can be done in a variety of ways.
- A hex “key”
- A hex insert bit
- A hex socket that fits on a wrench
A hex key is perfectly acceptable (and economical) method of driving these fasteners. If purchasing a set of hex keys, look for one which has good length to it and the long side of the key having a ball drive. The ball drive is extremely useful as it allows you to do turn the screw while not being completely square. A normal hex key requires you to be perfectly aligned to the screw. The other options of a hex key insert bit or hex socket will just allow you to do the job faster as they can be fitted to a drill or socket wrench and may also allow you to exert higher levels of torque.
The Torx screw head was designed in the late 1960s and its 6-point star shaped head was suited to mass production fastening tools. The shape tends to draw the tool into the head under load, greatly reducing the chance the tool will “cam out” (disengage with the screw head) at high torque values (unlike a Phillips head, where the screwdriver will slip out of the head at high torque). \
This fastener design is becoming more prevalent; however they can be done up very tightly from the factory. Take care not to break your tool or yourself.
Depending on the model of motorcycle that you own, you might find Torx fasteners and therefore have a need to purchase similar tools. Similar to the hex fasteners, you can purchase key, insert bits, or Torx sockets.
In both hex and Torx cases, socket versions like below can get much better leverage on a socket handle (as opposed to the key), and the insert bits are only available in the smaller sizes.
Use of screwdrivers
With all screw designs, the driving tool must have constant force applied to keep the tool engaged with the head of the screw. Then the operator must apply a twisting force to the tool to either loosen or tighten the screw.
If the force keeping the tool engaged to the screw relaxes, but the twisting force remains, then the tool will often cam out, meaning it will disengage with the screw. With quality tools, the slip of the tool out of the screw tends to damage the screw head.
The aim is to prevent damage to the screw head where possible. Occasionally it is unavoidable. If a steel screw is fitted into aluminum, corrosion can cause them to lock together very tightly.
When dealing with stubborn screws, orientating yourself to place some bodyweight over the screwdriver to help keep it pressed into the screw head. Then slowly and gently apply a twisting force to break the screw loose.
This is a special aspect of screwdrivers and whilst not essential, having one can be extremely helpful. When screws are particularly tight as mentioned above, it can be hard to get enough pressure on the screw head to stop the screw drivers slipping out. Have this happen enough times and soon you’ll soon have a stripped screw head.
This is where an impact driver comes in. Originally these were a handheld tool, where various screwdriver tips can be fitted to the head of the driver, which are then inserted in the screw, held down against the screw and the other end whacked hard with hammer.
When the hammer hits the impact driver, this pushes the driver forcefully into the screw face whilst slotted drives in the impact driver rotate the head.
These days you can buy cordless impact drivers, which are designed to mimic the handheld impact driver motion in a cordless drill. If you have one of these, they can certainly be used in such situations, but be aware that there is still a danger of stripping screws as the powered impact driver has the ability to spin up quite quickly, sometimes more than you can exert pressure to keep it on the screw.