When smoke starts to pour out of your motorcycle’s exhaust, it can alarm you, worry you or embarrass you. In short, it can ruin your day. It’s a clear indication that something’s wrong and a problem you need to address immediately. But what’s causing the issue? You’ve never missed a service, regularly check your oil and take good care of your bike, so why is the motorcycle exhaust smoking?

Motorcycle exhausts are devices that are conceptually simple yet complex in their workings, with every part serving an important purpose. They’re designed to blow the gas created by your engine’s combustion chamber away from you (and your pillion), so you’re not breathing it in. Your bike’s exhaust also helps turn that carbon monoxide into carbon dioxide, which is easier on the environment and stops your engine from being frighteningly loud.

Motorcycle exhaust parts like the muffler, the resonator, the catalytic converter and the piping unite to form an elegant and effective device that helps to define the very shape of a motorbike, not just the quality of ride it provides.

In most cases, a smoking motorcycle exhaust is a sign that some fluids that shouldn’t be there have found their way into the engine. Different coloured smoke indicates different problems, but excessive smoke is always a sign that something requires your urgent attention.

If you want the problem fixed fast, take it to Taverner Motorsports. Based in Bowen Hills, inner-north Brisbane, we can draw on our 40+ years of motorcycle experience to swiftly fix a smoking motorcycle exhaust no matter the cause of it.

But if you’re worried your bike is on its way out, don’t panic. Here are the most common reasons why motorcycle exhausts start blowing smoke.

Causes of Smoking Motorcycle Exhaust

Vintage bike restoration

It’s worth remembering that a small amount of white smoke when starting your motorbike isn’t a cause for concern. During a cold start, most engines emit a little water vapour created by changes in temperature in the exhaust system. But this shouldn’t last any longer than a few minutes. 

If your motorcycle exhaust is smoking more than that, the problem is likely to be one of the following culprits:  

Engine running too rich

Running rich’ is what happens when there’s too much fuel and not enough air in your motorcycle’s engine. This is frequently due to an exhaust leak or a recently replaced exhaust that wasn’t tuned correctly. Running rich leads to excess amounts of unburnt fuel going into the exhaust and coming out the other side as thick black smoke.

Coolant leaking into the engine

Many things can cause coolant to leak into the engine: a faulty hose or clamp, a loose or broken drain plug, or punctured radiator fins. If you have white smoke coming from the exhaust even after the bike has well and truly warmed up, you’re probably looking at coolant in the engine.

Oil leaking into the engine

Blue or grey smoke is a tell-tale sign that oil is leaking into a motorbike’s combustion chamber. Common causes of this issue include a clogged PCV valve and worn-out piston rings.

Incorrect oil

A poorly selected type of oil can also be the cause of a motorcycle’s exhaust smoking. Fortunately, this is one of the easier problems to fix.

Burning wires

It’s worth checking the source of the smoke because if it turns out it’s coming from someplace other than the exhaust, you could have wires burning. Burning wires produce a very dark, almost black smoke accompanied by the smell of burning rubber. If you ignore this problem, you may end up facing an electrical fire.

Solutions for a Smoking Motorcycle Exhaust

Vintage bike restoration

How do you fix a smoking motorcycle exhaust? It probably comes as no surprise that the answer to that question depends on the cause of the problem.

With some tools, some technical knowledge and some research (plus access to the right motorcycle exhaust parts), you can fix a lot of the issues yourself. But if you’d prefer to save yourself the hassle, take it down to Taverner. Motorcycle exhausts are second nature to us, and at this stage, there’s nothing we haven’t seen.

If the smoke is caused by faulty piston rings, you can begin with a compression test. Test each cylinder’s pressure separately and replace the cylinder if its pressure is low. Unless you’ve done this before or have a lot of technical knowledge, this is one undertaking it’s best to let a motorcycle mechanic handle.

If it’s an engine oil leak causing the smoke from your exhaust, you’ll need to either tighten the bolts or change the gaskets. For this task, it’s important to look up your manual and tighten the bolts to the correct torque specs or take it to the mechanic. Trying to tackle this task yourself when you’re unprepared can cause more oil leaks or damage parts of the engine.

Prevention is always the best approach, and there are some ways you can prepare so that you have a better chance of avoiding your motorcycle exhaust smoking entirely.
Vintage bike restoration

Check your coolant levels before you go for a ride. While you’re riding, keep an eye out for warning signs, such as the coolant levels dropping with no visible leaks present. Keep a close watch on the engine temperature, especially if the weather is hot. If the engine temperature rises suddenly, it could be a sign of an issue with the head gasket.

And if your engine starts to smoke, don’t ignore it or continue to ride around like nothing is wrong. Take it to Taverner, and we’ll get on top of the issue, preventing more problems from occurring.

Of course, one of the most effective ways of taking action to prevent problems is to book your motorbike for a regular service. Regular servicing at six-month intervals gives your mechanic a chance to spot potential problems early, and it also means a safer, more pleasant ride for you.

Get Your Motorcycle Serviced at Taverner Motorsports

Vintage bike restoration
If you’re eager to prevent motorcycle exhaust problems before they occur, book a motorbike service with Taverner Motorsports.

Taverner offers both major and minor services, plus custom workshop services and motorcycle exhaust parts.

Our major service includes replacing the engine oil, changing the filter and taking your bike for a test drive. We’ll diagnose any problems early and give you the chance to fix them long before your motorcycle exhaust starts smoking.

From our beginnings in Bathurst, NSW, in 1975 to our current location at 159 Abbotsford Road, Bowen Hills, Taverner has spent decades perfecting our craft and mastering the art of servicing, repairing and customising motorcycles.

Whether you need a cure for your smoking motorcycle exhaust or you want to prevent the situation from happening in the first place, get in touch with the Taverner team.