I’m sure that I don’t have to tell you that motorcycle exhausts can get really damn hot. You can feel the heat radiating from the exhausts when sitting at a stoplight, and you can even see it when the headers are glowing red-hot.
But how hot do they get exactly?
Whether you’re simply curious or want to know which high-temperature paint you should use on your exhaust – well talk about all of that and more in this article.
How Hot Does a Motorcycle Exhaust Get?
Motorcycle engines are high high-revving and very power-dense, but not as efficient at burning the fuel as diesel engines, which are around 40% more efficient (it’s also the reason why diesel engines run much cooler than gasoline engines). Because of that, a lot of the stored chemical energy in the form of gasoline is turned into excess heat rather than mechanical work.
With that said, the temperature of a motorcycle exhaust usually stays in the 600-1200 °F range. The exact temperature at any given time varies greatly and depends on a ton of factors, like RPMs, distance from the combustion chamber, airflow, ambient temperature, etc.
To give you a better idea, we measured the INSIDE of the exhaust at the first bend on the headers with a thermocouple. The test was done on a Suzuki GSF400 Bandit, which revs up all the way to ear-screeching 14000 RPM.
|Idle (2000RPM)||687 °F|
|Cruising (6000RPM)||903 °F|
|Full Throttle (14000RPM)||1345 °F|
Now, this is a bit of an extreme example, because the GSF400 has a very high-revving engine, thus most motorcycles probably wouldn’t get that hot. Again, the temperature of the exhaust depends on a lot of factors, and I bet that the exhaust stays much cooler on lower-revving motorcycles, like cruisers.
Another thing to note is heat dissipation throughout the whole length of the exhaust. The exhaust gases coming from the combustion chamber are hottest at the start of the headers, where they bolt onto the engine, and will gradually cool down as they go through the exhaust pipe.
You can easily see how hot the headers get just by their discoloration, which gradually decreases and returns to chrome at the junction.
When the exhaust gases reach the muffler/slip-on, they’re already cooled down quite a lot, therefore the temperature of the muffler usually stays in the 300-500 °F range. Most if not all mufflers are insulated with an air gap and at least a single muffler jacket – this prevents the muffler from getting extremely hot on the outside and makes it look beefy as a nice side benefit.
Because of that, the outside of the muffler stays at a much lower temperature than the inside.
Which High-Temperature Exhaust Paint Should I Use?
Painting motorcycle exhausts has always been an issue for riders. You prep the surface, paint the whole exhaust, ride for a few months, and then the paint starts flaking off at the headers.
The reason why that happens is people use cheap paint and fail to cure the product properly. Motorcycle exhausts get extremely hot, especially at the headers, and your average high-temperature paint that’s designed for cars will never last at such temperatures. Always try to get the highest temperature paint that you can find.
Luckily, there are a few brands that can take the heat, like the VHT FLAMEPROOF. Remember to follow the curing instructions exactly – painting surfaces that reach extreme temperatures takes a lot of prep work, otherwise, it just won’t last and you’ll be left disappointed.
Motorcycle exhausts get very, very hot – from 600 to 1200 °F to be exact. The temperature at an exact moment depends on RPMs and the distance from the combustion chamber.
When you’re really giving it the beans, the area at the headers, right where the headers bolt up to the cylinder head, can get above 1200 °F. The temperature of the exhaust pipe gradually decreases the further you go from the headers and ends up at around 300-500 °F at the muffler.
Jake is the site’s primary contributor.
Motorcycles and automotive repair have been a big part of his family for generations, therefore it’s only natural that he decided to become a heavy-duty diesel tech.
Outside of work, you’ll find Jake restoring and riding rare street bikes and ATVs.