My Motorcycle Is Smoking: Why? Four Reasons and How to Fix it

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It can be frustrating to try and fix a problem on a motorcycle. Though motorcycles are a lot more simple than other vehicles, there are still various reasons and possibilities as to why it’s behaving a certain way.

Excessive smoke from your motorcycle can quickly ruin your day. It’s also one of those issues that you can’t ignore and likely have to address quickly.

My motorcycle is smoking. Wearing piston rings in the engine can cause motorcycles to smoke. This is because oil seeps into the combustion chamber. Motorcycle smoking can also be caused by an external engine oil leak that burns from the heat of the engine, poorly grounded wires, as well as newly installed exhaust wraps that haven’t fully cured themselves yet.

I’ve owned over a dozen motorcycles over the last few years and ran into this problem a handful of times. Here’s what I learned about the problem and how to fix it.

Why Motorcycles Smoke

It is important to immediately address any excessive smoke, no matter what the situation. Smoke is mother nature’s way of warning us that something isn’t quite right.

Having smoke come from your motorcycle isn’t a rare occurrence among these types of machines. In fact, it’s almost pretty common, especially with older motorcycles. But it can be scary when you see it and you’ll probably want to fix it quickly because it’s also pretty embarrassing.

The most common reason your motorcycle is emitting excessive exhaust smoke, especially in older models, is worn piston rings. Piston rings seal your engine from two different compartments. It seals the top half, which is known as the combustion chamber, while sealing the bottom half, which is known as the crankcase, of your cylinder.

Your crankcase is sprayed with oil, and the oil is splashing up against your piston and other parts of your engine to keep them well lubricated.

But you don’t want oil getting past the piston rings up into the combustion chamber because you want the gas combusting instead of the oil. This can quickly drain your oil, which can lead to overheating your engine. It could also cause excessive smoke from your exhaust. This is typically caused by regular use of the bike and normal wear.

Smoking is the second most common reason motorcycles smoke. This will create smoke directly from the engine.

If you have any oil on the engine, you should see this after you’ve stopped riding. You can see between the fins of your engine. Usually, the cylinder is in pieces. This allows you to inspect the lines surrounding the engine and any oil leaks from the seals.

If you have smoke coming from somewhere else on your motorcycle that’s not from exhaust or the engine, you could have wires burning. This type of smoke is extremely dangerous because it can ignite an electric fire.

A motorcycle that was wired incorrectly touched the metal frame caught fire once. I had to replace the fuse. This type of fire will often be accompanied in some way by the smell and taste of burning rubber. Check your wiring harness and wires for burns, scorch marks or melting plastic. Before you start your motorcycle, it is important to fix this immediately.

A motorcycle could also smoke if it has new exhaust wrap. This is a fiberglass based product that’s wrapped around exhaust pipes for both looks and as a safety guard to prevent burnt feet and ankles.

Once the fiberglass is installed, it will burn off and harden while you ride. They will smell and smoke for a few hours after your bike is started. If these have been installed recently by you or your shop, this is normal.

How to tell what the issue is by the type and smell of the smoke

Sometimes it is easy to see where the smoke from your bike is coming from. It can be difficult in other cases because smoke may seem like it’s coming from one place but could really be from a different source.

If it’s hard to visually see, your motorcycle can help you figure out exactly where the smoke is coming from by what color the smoke is and what the smoke smells like. Smoke will naturally have a general odor, but each of the issues described above will have its own distinct smell.

You will notice excessive smoke coming from your exhaust pipes if the piston rings are failing. It will typically be a white smoke with an occasional blue tint. It will also smell like burning oil, which is a distinct smell from normal exhaust.

When you have an external oil leak that’s burning from the heat of your engine, Again, you’ll notice the white smoke with a blueish tint. It will also smell like burning oil. Because the exhaust pipe and engine are typically a foot apart, it is easy to tell which one you have.

You can also distinguish the smoke from your motorcycle’s wires. It will produce a dark, almost black smoke that is accompanied by the stench of rubber burning. Because the rubber around the wires is burning.

If you smoke from new exhaust wraps, the smoke will look almost like steam and be white. It releases a strong odour of burned fiberglass, which can be very unpleasant.

How to fix smoking issues

Once you’ve figure out the source of the smoking on your motorcycle, you’ll probably be left wondering how to fix it. Many of these problems can be solved by you if your basic tools are available and you’re willing to do some research. Click here for my recommendations.

It can be a little tricky when you’re dealing with failing piston rings inside your engine. Start by performing a compression test of the engine. You can test the pressure in each cylinder individually. If the pressure is too low, you will need to replace the piston rings. Unless you’ve done this before, this is the one fix I recommend you take into a shop and have them do.

You may suspect that your motorcycle is smoking because of an oil leak. You will either need to replace the gaskets or tighten the bolts. It is possible to change the gaskets yourself, but you’ll need a little experience to accomplish this. See my article for more information on changing the gaskets of your motorcycle engine.

If you are going to tighten the bolts on your engine, look in your owner’s manual (or you can probably look it up online) and tighten the bolts up to the proper torque specs. You can also take the engine to a mechanic who will retorque it for you.

It’s important that you don’t free-hand the tightening of the bolts on your engine. This could lead to more oil leaks and cracking of engine parts due to tightening bolts. I’ve made this mistake before and it’s not worth it. Do your research.

You can inspect the wiring on your motorcycle to find the issue. To prevent future problems, replace the wire immediately and make sure you splice it correctly. Make sure that the wire is properly grounded and protected with a fuse. Also make sure it won’t rub up against anything such as the front or back tire.

After a few hours riding, smoke from exhaust wraps should disappear. If you’ve noticed it is not stopping, you may need to rewrap the exhaust pipes and be sure to get them wet first and install them tightly.

What is the Normal Smoking Level?

You might be wondering if your motorcycle is having any problems or if it is just normal smoke. This will help you to determine if there are any other issues with your motorcycle.

Some smoke can sometimes come out the exhaust pipes. Motorcycles don’t have a catalytic converter that converts the exhaust fumes into non-noxious gases. This will result in a bit more smoke than with other vehicles.

The exhaust should not produce too much smoke. You should only notice it slightly. Also, the smoke should be faintly white. The cold temperatures will make the exhaust more visible in cold months. Other than this, You should have no smoke coming out of any other part of your motorcycle.

Similar Question

Why is my bike idling so high? If the motorcycle is getting too many air and fuel in low speed or neutral positions, it may idle high. This can be caused by a bad throttle spring, an out-of-place throttle handle screw, a loose throttle throttle spring or a sticky throttle. For more information, click here.

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