Kawasaki Vulcan 900 Problems – These Are Main Issues with the Bike

Kawasaki Vulcan 900 model is deservedly highly placed on the elite list of motorcycle cruisers. Many fun-seeking American riders have fallen in love with this mean machine for good reasons. Its five-speed transmission capability and its 5.3 gallons tank ensure you go fast and far. Likewise, is its 903cc, 4-stroke V-Twin engine, liquid-cooled, which remained one of the largest of its kind for many years.  

Apart from speed and ruggedness, Kawasaki Vulcan 900 also possesses features that offer safety and comfort. Examples are the insanely efficient front and rear brakes. This feature gives you higher control over the bike when you want to bring the bike to a halt in case of emergency.

Another is its coolant temperature warning light that helps you protect the engine from overheating and the stylishly designed seat that curves at an angle that matches the most comfortable stride-sitting posture.

Despite all these intimidating features, Kawasaki Vulcan 900 is not without its problems. Of course, some are commonplace and too general to deserve special attention, but a mention may still be necessary. This article does justice to that with an in-depth analysis and identification of three main problematic issues with the Kawasaki Vulcan 900.  

Let's dive in!

1. Irritating Noise from the Engine

It's normal for engines to make some noises - after all, they comprise moving parts. However, any noise coming from an engine must be typical of it when in good health, and that's not the case with these disturbing noises associated with Kawasaki Vulcan 900 engine.

We looked into this issue and identified three problems that may predispose this bike to this problem. Here we come:

• A faulty drive pulley

If you have been a Kawasaki Vulcan 900 owner for over a few years, you must have experienced this. After about 15000 miles, the bike pulley may start producing a persistent squeaking noise which worsens progressively. In most cases, it comes from the contact point of the final drive to the pulley.  

In practice, when you engage the gear and power the engine, the belt (final drive) transfers the engine power from the pulley to the wheel. This process is supposed to be a smooth system function, but things sometimes go wrong. This is when issues like noise from the pulley arise.

Unfortunately, it is not easy to precisely identify the cause of this issue. A likely cause, however, is an incorrect belt tension. This happens when the belt tension is too loose or tight, depending on the situation's sensitivity. Meanwhile, either is a problem.

Where the tension is loose, the belt may partially run off the edges of the pulley, thereby grinding against the engine and producing a nasty sound.

Another possible cause of the noise from the engine is when there is a broken part. It may sometimes be something seemingly negligible as a bent or broken washer that may grind against the pulley. If this is not detected and corrected in time, it may degenerate and lead to a complication - a worn axle connection, which is a greater problem.

This complication may cause the crankshaft RPM (revolution per minute) to skip as the drive pulley gradually loses grip of the axle.

• Oil pump failure

The oil pump on your Kawasaki Vulcan 900 can also be a pain in the neck. For Kawasaki Vulcan 900, this pump fails far too quickly. A clicking sound from the engine may signify an ailing oil pump. It may also present as a whining noise louder around the clutch area.

Though some owners reported that they started noticing this issue after they had gotten about 4,000 miles on their bikes, the data available show that the problem can surface at any point in time.

• Inexplicable noise

Unfortunately, this model of Kawasaki Vulcan can keep producing some noise you will have to learn to live with. It seems the engine produces this kind of noise without any detectable fault.  

2. Clutch Slips

Another main issue with Kawasaki Vulcan 900 is clutch slips, whereby the clutch fails to disengage power transmission to the rear wheel. The result is that you will not be able to change gear or put the bike in motion from a standstill position. This problem is common to most other bikes, but Kawasaki Vulcan 900 can be particularly susceptible. 

A part of the associated problems with this issue is speed impediment - throttling stops being proportional to speed. Instead of the bike picking up progressively faster as you throttle, you get lots of noise and little speed because your gears are not engaging effectively.

Many different factors may be responsible for a clutch slip. First, a clutch slip may result when the engine has excess oil, which may occur if you are not using the recommended oil.

A second likely cause is thin/worn clutch plates. We found that Kawasaki Vulcan 900 clutch plates most probably wear off within a short time, which disappoints owners. Meanwhile, these plates are the main friction component in the clutch.

Their wearing means the wheels may not be able to keep pace with the engine because of failures in transmission. That happens when the clutch plates fail to completely engage, allowing the flywheel to spin faster or slower than them. This problem worsens when your vehicle's engine is at a high rpm.

Lastly, a slack clutch cable can also cause a clutch slip, even though this is the least problematic of the possible causes. This cable transfers the force you exact when you pull the clutch lever. But when the cable is slack, it leaves a snag of a space which causes the clutch to drag or slip.   

3. Electrical Problems

These problems are interwoven issues between the battery, stator, and regulator/rectifier - components that form your bike's charging system or what some call the electrical charging circuitry.

It is saying what's obvious to state that the charging system is very important to your bike. Certainly, the bike cannot work without a battery, but, in the same vein, the battery relies on the integrity of the charging unit.

As important as this unit is, Kawasaki Vulcan 900 does have a slew of peculiar problems in this area. In fact, we found that electrical problems are arguably the most significant issues of Kawasaki Vulcan 900, and the stator is the culprit 80% of the time. The other components share the remaining 20%.

The model's three-piece alternator comprising the rotor, stator, and regulator/rectifiers, is the saving grace that reduces the difficulties owners would have been going through. Though its three independent units work jointly, each has an individual lifecycle and can develop independent faults and be independently fixed/serviced or replaced.

The headache with Kawasaki Vulcan 900 charging system, however, is that for some yet-to-be-identified reason(s) cause one or more of these components spoil too quicker than they should.

To highlight the problems properly, let's go through every component of the electrical charging circuitry to understand how things work under normal circumstances.

• Battery

The battery, with the aid of the stator, produces AC (Alternating Current) power which the regulator/rectifier converts into DC (Direct Current). The battery has a role to play in the case of a regulator/rectifier failure. In such an instance, it (the battery) serves as a buffer for other electrical components, protecting them from damage even though there is an associated problem, as the battery can sacrifice itself doing this.

Where the battery goes on the fritz, your bike may not start, or you may have to make several attempts before it starts.

How to know when your battery is bad or dead?

• Key off voltage: in the neighborhood of "around" 12.6V range.
• Key on voltage: At least 12V - anything below indicates a critical problem. The battery is either dead or bad.
• Key on voltage after 5 minutes: Like in 2 above, it should be at least 12V. Anything below this point means the battery is dead or bad.
• Idle voltage: Depends on the bike.
• Cruise voltage: Anything between 13.8 and 14.5V is normal.

• Stator

The stator plays an essential role in the charging system and is responsible for creating electrical energy that your bike depends on to function to your satisfaction.

When the stator develops a problem, there are different symptom possibilities depending on the level of damage.

You may experience anything from no spark to weak spark or intermittent spark. Sometimes, it may become increasingly hard to start the bike. And when eventually it starts, the engine may perform abysmally low comparatively. When you notice any of this, buddy, it might be time to rebuild or replace the stator.

• Regulator/Rectifier

The regulator/rectifier is responsible for converting AC to DC. At the same time, it also functions as a regulator (as the name indicates), keeping the DC power at a maximum of around 14.5 volts. The DC is then routed back into the battery for storage.

When the regulator/rectifier fails, it puts the battery at a big risk, and it can even cause the battery to fry.

Final Words

Kawasaki Vulcan 900, though has some issues, its many strong features overshadow them. Plus, the problems are also fixable by either repairing the failing components or replacing them.