Preventive Bike Maintenance: The Fastener Algorithm
BY PAUL STEWART
When you ride, your motorcycle shakes. Even the smoothest running bike vibrates: it’s the nature of the beast you plan to travel on. Now add bumpy roads, and that vibration is magnified – but why should you be bothered?
Besides the welded parts (permanent fixtures) on your motorcycle, everything else is held together with a nut, bolt, or screw. In this article, let’s just call all of them ‘a fastener’.
If you look in your manual – whether it is a hard copy or an electronic version – you will find torque specifications; in Europe and other parts of the world, you will see Nm (Newton Meters). Every single nut, bolt and screw has a particular setting specified by the factory. In short, this is the tightness that a particular fastener needs to be in order to hold its item in place and not come loose.
This is all well and good; but add vibration and time, and a lot of these fasteners will slowly come loose. In addition, there is a very good chance you will not spot it until it’s too late and in some cases, the bolt or nut has long gone. If you over-tighten the fastener, it may destroy the thread rendering the fastener useless.
So, how do you stop this from happening and make your life easier?
Regardless of whether your bike is new or old, the same basic principals are at play. Make sure every fixture is checked prior to leaving: this will not only prevent fasteners from coming loose but will also potentially make your bike lighter.
Get your hands on a torque wrench. This tool is specifically designed to make your fastener adjustments exactly right, as specified in your bike manual. Using the torque wrench, you can adjust all your fasteners precisely.
Usually, you can rent a torque wrench from a part shop, or perhaps your friend can lend you one.
Checking A New Bike
You’ll need: your tool kit, a paint pen (torque paint pen, yellow or white are best for visibility) and some green, blue and purple thread locker. On a brand new bike, all your fasteners will have been specifically tightened to the correct torque amount at the factory.
Grab your pen, and start at the front of the bike. Go from the front to back, side to side and top to bottom using your paint pen. You are going to put a dab of colored paint on all your fasteners – head of a bolt for example and a line to what it is tightened down to. See below.
As you’re doing this, put a dab of green thread locker on that same fastener between the item and what it’s attaching to.
A good idea at this time is checking your tools. As you’re marking your bike, have your toolkit at your side. This will help you double – check that you have every tool you need on the road. Once you have used it, put it in a separate bucket. If you have a tool missing, go and get it now – from tools you already have, or maybe you need to buy it. The logic here is once you have completely gone over your bike the chances are you will have touched virtually every nut and bolt. Now, when you empty that bucket, you will have all the tools you need. This is where you get to reduce weight! If you have duplicates of a tool, get rid of them. Check if you can get lighter and smaller tools instead of the ones you have now.
Checking An Old Bike
On a used bike, you will need your tools, paint pen, green thread locker and a torque wrench.
Go from front to back, top to bottom and side-to-side on the bike, add a dab of green thread locker, torque to spec (using that torque wrench), then mark the bolt with the paint pen. If your bike is a few years old, it’s likely that the fasteners have been touched already. Don’t just adjust them – loosen them first, then torque them down. Why? Well, the previous owner or the bike shop may not have used a torque wrench and possibly over tightened those fasteners. You need to be certain, and this is the only way to be certain it is correct.
Why are the torque specifications important? Here’s mechanics’ joke about the non-mechanical people when asked – “what’s the correct torque?’ ‘About a quarter turn before it snaps!’. Can you tell the difference between 60-inch pounds and 72-inch pounds of torque? Probably not, so that’s why it’s best to know exactly where your fasteners need to be.
Now that you’ve marked all your fasteners, you will be able to tell precisely how much you need to torque them if they become lose. You will also be able to tell if a fastener is becoming lose instantly: when you fill up with gas or take a smoke break, have a snooze next to your bike. You will be able to know if anything is coming lose at a glance! And, there is the added benefit: if you have to take your bike apart, you will now know approximately what the correct setting (make the paint marks meet again) is for a torque specification without having a torque wrench if you put the same fastener back in the exact same location.
Choosing The Thread Locker
A thread locker is an adhesive applied to the threads of fasteners. It literally locks the threads together, making sure that your fasteners won’t come loose.
What are the different colors of thread locker, what do they mean and what do you need?
Here’s the information from Loctite, the thread locker manufacturer:
Loctite® Red Threadlocker is the highest strength. This product cures fully in 24 hours and is available in both a liquid and as a semisolid anaerobic. The red products are so powerful that they require heat to be disassembled.
Loctite® Blue Threadlocker is of medium strength. Again this product cures fully in 24 hours and can be dissembled with hand tools.
Loctite® Green Threadlocker is recommended for locking preassembled fasteners, e.g. electrical connectors and set screws. The product is categorized as medium-to-high-strength for wicking. It is also available in a liquid form, cures in 24 hours and can be removed with heat and hand tools.
Loctite® Purple Threadlocker, also known as Loctite® 222™, has become one of our most successful products. Loctite® 222™ cures in 24 hours. It can also be used on low-strength metals such as aluminum and brass.
All thread lockers have a broad temperature resistance of -65°F to 300°F, some going up to as high as 650°F.
In simple terms, the green thread locker is a wicking compound, so it will work its way down the thread and set without you having to undo the fixing. It’s perfect to use on your bike without having to undo anything. It’s your initial set up before you leave.
Purple will be for your small nuts and bolts, things like carburetor screws and bolts smaller than ¼” or 6mm, as well as any aluminum bolts going into steel threads. It’s good to have a small tube of the purple thread locker in your tool kit.
Blue will be your go – to thread locker if and when you take anything apart. Just a small dab of this is all that’s needed to hold your fasteners securely together.
Red will be used on a few internal parts that you may never see and possibly on your rear sprocket and/or brake rotors; basically, parts that need to be very secure and rarely taken off, but when they do you’ll need to apply heat beforehand. Leave the red at home.
Only a small dab of the thread locker is required: put it right at the end of the screw, and it will work its way on all the threads as you screw that fastener together. You do not need to soak the fasteners in it!
Did you find the article useful? Share your own bike maintenance tips in the comments below!