Some people say that everything in life is about timing.
Then there are others like me. (Who makes things up as they go)
No matter what your views are, you have to agree that the timing chain in your motorcycle serves a crucial function.
So, if that chain gets loose, you need to fix it, pronto.
But how to recognize the symptoms of a bad tensioner in a timing chain in a motorcycle?
Keep reading to find out.
What is a Timing Chain Tensioner in a Motorcycle?
Let’s start with the basics.
The engine is an assembly of various inter-dependent components that need to function in harmony for the best performance.
(Does “engine orchestra” sound cool? Thought so!)
And to ensure a smooth operation one key element is…
You guessed it right – timing.
Two fundamental movements that need to be timed precisely are those of the crankshaft and the camshaft. The crankshaft controls the forward and backward movements of the piston. The camshaft controls the opening and closing of the engine chamber valves with perfect timing.
The chain or belt connecting these two movements makes sure that these two functions are in sync. That’s why it’s named the timing chain. Some also call it the “cam chain”.
What happens if the chain fails and the valve timing goes off?
Think of disfigured valve seats, broken pistons, and more catastrophic damage. Chances are your engine interiors will look like the traumatized victims of an alien invasion.
For the first time, it dawns on you the bike would simply not run without this chain. Still, it’s one of the least discussed aspects of the engine.
One thing is, this is a small roller chain enclosed within the engine and can easily be overlooked (Well, size does matter.)
Note, the chain is connected between the crankshaft sprocket and the camshaft sprocket. To be more specific, the crankshaft sprocket is smaller than the camshaft sprocket.
The timing chain is precisely engineered to last the lifetime of an engine.
Moreover, it’s shielded from the environment and continuously bathed in oil. So, the overall maintenance factor is low.
Even so, it may stretch or wear out with time. Due to the high pressure and heat in the engine compartment, it might stretch or loosen up. And that can result in significant performance loss.
That’s why the engine block comes with a chain tensioner for adjusting the chain. It also absorbs shock and vibrations to ensure that the chain functions smoothly.
And as with all other chain drives, the timing chain has to be kept with the right amount of tension. Too much slack or excessive tension – neither is good for the chain.
Some bikes come with an automatic chain tensioner, which is relatively easy to adjust. Beyond that, there are other tensioners that require manual adjustments.
Basically, there are two types of manual chain tensioners: the mechanical type and the hydraulic type. Both these types ensure that the timing chain fits snugly on the sprocket teeth and doesn’t come off.
Loose Timing or Cam Chain Symptoms in a Motorcycle
As with most mechanical issues, there are a few symptoms of a loose or worn-out timing chain. Staying alert and watching out for these signs will save you from replacing the engine. (And a few thousand dollars.)
How do I know if my motorcycle’s cam chain is loose?
Take a look.
1. It gets noisy
With a loose or a worn-out chain, you might find disruptions in the even growl of the engine. The excessive vibrations in a chain can cause an unusual rattling or ticking sound when the engine is idling. In some cases, the excess slack in the chain might cause the valves to run off-sync. That can result in noise or vibrations during idling or when the brakes are applied.
2. Frequent misfires
If the timing chain is stretched out, it can affect the timing of the valves. As a result, the engine will misfire. At other times, the engine performance will drop and you will feel a lack of power while accelerating. The fuel consumption can also increase.
3. Broken metal pieces
When a loose chain rubs with the other parts of the engine, it can result in metal debris. (I have seen this happen to a friend. For a true motorcyclist, it’s really upsetting to see an engine breaking up from the inside.)
In fact, a jumping belt can damage the valves and the pistons. The metal pieces can get collected in the oil pan. During an oil change, if small metal pieces are present in the oil, there’s an issue with the chain.
4. Failure to start
Another symptom that you may notice is problems while starting the motorcycle. Even if it starts, the ride will not be smooth. Since the valves are not opening properly, there isn’t enough compression inside the engine to deliver the right level of power.
How to Fix a Loose Timing Chain?
In bikes with automatic tensioners, the chain adjustment is performed automatically. However, you may need to adjust a nut or loosen a bolt to activate the mechanism. In the case of chains with manual adjustments, you need to do the hard work manually. Refer to your owner’s manual for the guidelines.
Sometimes the tensioner might malfunction and need replacement. Replacing a bad cam chain tensioner is a relatively simple task.
After adjustments, if you still notice any of these symptoms, visit a mechanic for a proper evaluation. If the chain is worn out driving around will be too risky.
Note, regular oil change and proper engine maintenance are essential to help the chain function efficiently. Without the right supply of lubricating oil, the chain is bound to get damaged.
Replacing the chain isn’t so simple. The exact process will depend on the engine type and design. If needed, you might have to change the sprockets too. Take my advice and don’t attempt it on your own.
Most importantly, the cam timing should remain exactly the same after the replacement.
Frequently Asked Question
How long do timing chains last?
Generally, timing chains are designed to last the life of the engine. They can easily last over 1,50000 miles. Still, some owners prefer to replace them earlier to ensure no drop in performance.
Can you drive with a bad timing chain?
Driving with a bad timing chain is the worst idea. You can cause serious damage to the engine and compromise your safety by doing so.
How much does a timing chain cost to fix?
The cost of fixing a timing chain depends on multiple factors. It’s hard to specify a ballpark figure. You may need to spend anywhere between $500 to $1200 depending on the labor charges.