One of the questions that many Harley-Davidson riders can sooner or later have is regarding the longevity of Harley engines.
I find those questions completely normal and justified. However, these are the exact type of questions that many sellers and dealers may try to avoid simply because they are not easy to answer.
How long do Harley-Davidson engines last? Harley-Davidson engines typically last between 60,000 to 250,000 miles. However, there are reports of Harley-Davidson engines lasting as long as 400,000 miles to even 1,000,000 miles. How long a Harley-Davidson engine will last depends on a number of factors like proper maintenance, care, riding style, and more.
These numbers are good, and all but things are not always that simple. How long a Harley Davidson engine is expected to last and how long it would last in reality can be two very different things.
Below I go into more detail.
How long do Harley-Davidson engines last on average?
Some of the really old Harley-Davidson engines were known to be fairly unreliable, however, that was a long time ago. Unfortunately, the bad reputation persists even today.
Today Harley-Davidson engines are reliable and can last a long time.
Some of the best Harley-Davidson engines that tend to last a really long time are:
- Harley-Davidson Evolution engine (EVO)
- Harley-Davidson Twin Cam engine (TC)
- Harley-Davidson Milwaukee-Eight engine
There are plenty of riders who have on their Harley EVO engines more than 100,000 to even upwards of 145,000 miles.
Many Harley riders have put on their TC engines more than 90,000 miles, as well.
There are also some riders that have put on well over 200,000 miles on their Harleys while barely running into any problems. There are also examples of Harley engines that have put on upwards of 400,000 miles.
After all, there is a good reason why Harley-Davidson motorcycles have claimed second place in this owner satisfaction survey by Consumer Reports. Although reliability-wise, in another Consumer Reports survey, Harley-Davidson motorcycles fell somewhere in the middle. (Of course, that survey was not focused on engine failure only.)
Things can be very different when it comes to modified Harley-Davidson motorcycles, however, because poorly done modifications can significantly lower the engine’s life expectancy.
This is also why most people agree that the number one reason why motorcycle engines fail is because of the user. Although there can always be some lemons in the vast majority of cases, a Harley-Davidson engine would fail due to an owner’s fault.
What is the longest-lasting Harley-Davidson engine?
When we are talking about how long Harley-Davidson engines can last
The most mileage documented on a Harley-Davidson engine was 416,000 miles, which have been accumulated on a 1987 Harley-Davidson Tour Glide. There was even information stating that Harley intended on studying the engine because of how long it lasted.
However, in 2009 a former Wisconsin senator Dave Zien put 1,000,000 miles on his 1991 Harley Davidson FXRT. The motorcycle is now put on display at the Sturgis Motorcycle Museum and Hall of Fame.
What is the shortest a Harley-Davidson engine can last?
Harley-Davidson engines will typically last a really long time if they are cared for and looked after.
In some of the worst-case scenarios, you may have to do an engine rebuild at as little as 30,000 miles in certain instances. In theory, an engine can fail at any time depending on a number of reasons like poor maintenance, not following the manufacturer’s recommended instructions for breaking in new motorcycles, and more. Factory defects are also not completely unheard of either.
There are reports of some H-D engines having an oil leak at as little as 6,000 miles, while other engines can remain failure-free for more than 100,000 miles. As already noted the bearings, pistons, and valves should stay good a really long time.
In order words, a new engine can fail even at a few hundred miles.
How long can Harley-Davidson engines last before they need to be rebuilt?
When we discuss how long Harley-Davidson engines can last, we should not overlook the fact that the engines will have to be rebuilt at some point. Rebuilding the engine should not be considered as an engine failure but more of a part of the routine maintenance and care.
Harley-Davidson engines can last between 30,000 to 150,000 miles before having to be rebuilt. When exactly they should be rebuilt depends on a number of different factors. The top-end usually needs to be rebuilt at 60,000 to 80,000 miles, while the bottom end of the engine might need to be rebuilt at around 80,000 to 120,000.
How many years can a Harley-Davidson engine last?
In terms of years, Harley-Davidson engines can last a really long time. If the engine has been properly looked after, routine maintenance and care have been performed regularly, and the engine has been kept clean, and the motorcycle has been stored in a suitable location, it can last upwards of 50 years.
On the other hand, poor maintenance, care, cleaning, and storing the motorcycle outside can reduce the lifespan of any motorcycle engine, and it could fail even in less than 10 years.
What affects how long a Harley-Davidson engine will last?
I have written about how long motorcycles last before, and it is important to understand that a number of different factors affect how long a Harley-Davidson engine will last.
Engine maintenance and care
Maintenance makes a huge difference and is the best friend to any motorcycle engine.
Harleys got their reputation as unreliable motorcycles back in around the AMF years between 1968 and 1981. However, their reputation as unreliable motorcycles grew back then also due to poor maintenance, repair, and modifications done by their owners.
In most cases, Harleys that are properly maintained and cared for are reliable, while, in comparison, motorcycles that have not been properly looked after can run into reliability issues.
The quality of the oil, the frequency of changing the oil and filters will also affect how long the engine can last. Since Harleys’ engines tend to overheat, the oil should also be changed more frequently compared to some other motorcycles.
Using cheap replacement parts can also cause a Harley to break down sooner than expected.
Part of the maintenance should also be considered the engine rebuilding, which is necessary if you want to keep the engine in good condition.
Naturally, the riding style of the rider is the second thing that should be taken into consideration.
More aggressive riding styles are usually detrimental to the engine’s life. Things like burnouts, wheelies, or drag racing can all lower the life expectancy of a motorcycle engine.
Keeping it in normal RPM ranges, including keeping the idle RPMs according to specifications, not abusing the motorcycle, and letting the engine properly warm-up are some of the ways to ensure the engine stays in good condition.
One of the easiest ways to negatively affect a Harley-Davidson engine is to let it overheat.
This can easily be achieved in many different ways. For example, revving the engine while at stoplights or riding at walking speeds, going into the red, or even by simply being caught in a traffic jam for longer periods of time on a hot summer day can lead to the engine overheating. It is possible for the engine even not to start, if switched off, until it has cooled down.
Although stock Harleys are fast enough, some owners will not really be happy with how they perform.
This can possibly be a result of Harley-Davidson keeping their older engine design. Although the 45-degree, air-cooled, pushrod engines have a very distinct classic look, they are also somewhat limited in terms of performance and power output.
As a result, they will do different types of performance modifications, which will ultimately affect the motorcycle’s reliability in the long run.