Is A Glowing Red Head Pipe Okay?

Wondering why you have a dirt bike exhaust glowing red and if it’s okay? Whether you just got your bike or you’ve had it for a while and it started getting red hot, you’re in the right place!

In this article, I’ll explain what it means when the exhaust is glowing red, whether it’s okay or not, the most common causes, and how to fix it.

Is a glowing red dirt bike exhaust okay?

No, but it doesn’t necessarily mean anything bad has happened…yet.
Is it “normal?” Yes.
Is there a way to fix it? Yes, there’s more than one possible solution, although there is one that stands out the most.

If the head-pipe is red, that means the engine is getting too hot and needs more cooling. You may not need any parts to fix this though; let me explain…

How long does it take exhaust to cool down?

If your head pipe is glowing red, you can shut the engine off and let it cool down so that it doesn’t do any (more) damage. This can take anywhere from 5-30 seconds to cool down and stop glowing, but it may take 5-15 minutes for the engine to cool down enough to safely ride again if it actually overheated.

Dirt bikes that most commonly have a glowing red pipe problem

Basically any 4 stroke dirt bike can have this issue, but there’s certain dirt bike models that have a frequent problem with the exhaust pipe glowing red.

• Suzuki RMZ250
• Honda CRF450R
• Yamaha YZ250F
• Kawasaki KLX230R

What Causes A Dirt Bike Head Pipe To Glow Red?

There are a number of reasons why it’s glowing red, and they range from simple to somewhat complex.

How long are you letting it idle?

There are two ways a 4-stroke dirt bike “cools”. Both of them require riding the bike, so don’t think you can stop and wait to let it cool down.

In fact, you want to do just the opposite. First of all, riding the bike gives it air-flow through the radiators (If it’s liquid-cooled), naturally.

So if you’re standing still, the cooling system isn’t going to do a whole lot. This is the most common issue for beginning riders and trail riders that do tight single track. The more you stay moving the better.

Gas Cools It

The next possible solution is similar to the first, but in a different way. You now know that riding at higher speeds will reduce the chances of overheating because radiators need air-flow.

Gas is the other cooling part. The more gas going through the cylinder head and combustion chamber, the more it will keep it cool, to an extent.

Like before, if you’re sitting with the bike idling, it’s not getting enough gas to burn and keep cool, even if your jetting may be correct (although, lean jetting can also cause overheating problems).

Do air-cooled dirt bikes overheat?

A lower-performance air-cooled trail bike should not have a glowing head pipe from idling. If that is the case, then the jetting is too lean, or the EFI is too lean and needs to be richer.

This can be done with a bigger pilot jet for a carburetor, or richening the EFI system with a fuel programmer.

And if you want to improve your trail riding skills so that you stay in control and prevent bad crashes, I have a super quick and practical training guide that shows you the basic techniques you need here.

Jetting too hot

If your dirt bike has a carburetor, then some proper jet tuning can make a huge difference in how your bike runs.

If everything is working well, but the jetting is too rich or too lean, then your dirt bike may be: hard to start, have poor throttle response, overheat faster, be less reliable, and more.

Jetting that is too lean will cause the engine to run hot because it’s not getting enough fuel to properly cool it.

Exhaust change without EFI tuning?

Does your 4 stroke dirt bike have fuel injection? Making an exhaust, or even a modification to the engine or intake will make it run differently.

The EFI on most dirt bikes is an open-loop system. This means it only takes account of the air temp/humidity.

What’s the result?

The system doesn’t know if it’s running the stock exhaust or no exhaust at all, which will greatly affect the air-fuel mixture. It only adjusts the fuel mixture when the climate you’re riding in changes.

When to get a fuel tuner on your 4 stroke

So, if your 4 stroke is running hot after an exhaust system change (even just a slip-on), there’s a good chance that you need to get the EFI tuned.

This might be a new ECU and controller, just the controller, or maybe your specific bike has an app available to tune it with WI-FI.

Valves wear out quicker with heat

It’s not necessarily the entire engine that overheats from a lack of gas. It’s the valves that start to heat up and eventually burn out.

If you’ve been around 4-stroke motocross bikes at all, you have probably heard the term “Burnt a valve.”

Well, this is one of the main reasons why it happens. The valves just get too hot too many times, causing them to burn up the edge and lose all compression. It’s better than dropping a valve, but still can be a costly repair.

How to make your valves last longer

Properly warming up your dirt bike is part of it, which is why I never let my four-strokes idle for very long when I first start them up.

How do I know this, you ask? Well, I know of many people that have burnt valves more often than usual, and it wasn’t coincidence. No, it was because they putt around on their bikes.

Not only does riding your bike harder and faster give it more air to cool it down, but it also gives it more gas to keep the valves cool, increasing longevity.

Modern 4-strokes are made for “putt-putt” riding…

All in all, a 4 stroke motocross bike is made for one thing; to be raced, and raced to its potential. You don’t have to out-ride yourself, and I suggest you don’t. Mastering the fundamental techniques is the key to riding faster and safer.

But, when you ride a modern liquid-cooled 4-stroke, whether it’s an MX bike or enduro bike, at slow speeds, it’s going to get hot quicker.

Mud stuck in the radiators?

Maybe you ride in the PNW or somewhere that gets a lot of rain. Muddy trails are not only harder to ride, but they’re harder on your bike.

Mud sticks to parts, including your radiators, which can cause your dirt bike to overheat, steam, and possibly make the head pipe glow red if it doesn’t cool down.

So, regular checks and cleaning of your radiators and engine can greatly reduce the chance of your dirt bike getting too hot and damaging the engine. Using some foam for the skid plate (Amazon) or between the gaps in the frame will prevent mud build-up and also keep your bike lighter – mud is heavy!

Dirt bike running hot after sitting in storage for months?

Did you just pull your bike out of storage and now it’s running hot with the head pipe glowing red. You haven’t changed anything since you rode a few months (or possibly a few weeks) ago, so what’s causing it?

If it’s carbureted, then it’s most likely due to it being dirty. The jets and passages are so small that it doesn’t take much of a spec or gas breaking down to gum up and block it.

What old gas does to the fuel mixture

This changes the air-fuel mixture because less gas is getting through the partially blocked passage. Less gas = lean and running hotter.

A quick draining of the float bowl may get sediment that settled out, but a carb that’s been sitting for a while may need a full and proper cleaning.

Dirt bike exhaust glowing red causes

The most common causes of a dirt bike head pipe glowing red are:

• Idling too long
• Dirty carb
• Engine is not getting properly cooled
• Improper jetting
• EFI not tuned correctly
• Sitting in storage too long

Free ways to prevent overheating

Want to learn how to keep your dirt bike running cool? These tips are Free to do and will help prevent a catastrophic failure that could leave you stranded in the middle of nowhere. Click here to learn how.