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Harley Automatic Primary Chain Tensioner Problems? Read This

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Navigating the twisty world of bike mechanics can often seem daunting. When it’s your covetable Harley at stake, uncertainty is not an option. If you’ve been losing sleep over the buzz around the automatic primary chain tensioner on your Harley Davidson, you’ve hit the right pit stop. This article intends to delve into the underappreciated complex world of primary chain tensioners, their significance, and the problems that you may confront. Armed with the insights of experienced hands, you will soon be ready to take the reins, understanding what could go wrong, how to detect a fault, and the right measures to correct the elusive Harley automatic primary chain tensioner problems. Get set to fuel your knowledge tank with unfiltered, practical, and actionable advice drawn from hardcore Harley Davidson experience. Prepare to be enlightened and enjoy a smoother ride!

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What Problems Are Encountered With Harley’s Automatic Primary Chain Tensioner?

Image highlighting the automatic primary chain tensioner in a Harley transmission

The Harley automatic primary chain tensioner is designed to maintain proper tension on the primary chain, ensuring smooth operation and longevity. However, some owners report that the tensioner can over-tighten the chain, leading to a range of issues including premature wear of the chain and bearings, and in some cases, catastrophic engine damage.

Community Reports

Many Harley owners have shared their struggles with the primary chain tensioner, particularly issues with over-tightening. For instance, one rider recounted how their tensioner ratcheted up too tight, causing excessive stress on the chain and bearings. This highlights the practical challenges faced by riders and the solutions they’ve found, such as switching to manual tensioners like the Baker Armored Attitude Adjuster.

How To Tell When The Chain Is Too Tight

Identifying an over-tightened primary chain is crucial in preventing further damage to your Harley. Here are key indicators to watch out for:

  1. Excessive Noise: An over-tightened chain often produces a distinct rattling or grinding noise, especially noticeable during low-speed maneuvers or when the engine is idling.
  2. Hard Shifting: If you find it Difficult to shift gears, or if the gear shifts feel unusually harsh, it could be a sign that the primary chain is too tight, causing undue strain on the transmission.
  3. Vibration: An increase in vibration felt through the footpegs or handlebars can indicate that the chain tension is too high, leading to excessive stress on the engine and drivetrain components.
  4. Visual Inspection: During a visual check, if the chain appears taut with little to no slack, it’s likely over-tightened. The chain should have some play to accommodate the engine’s movement.
  5. Wear Patterns: Inspect the sprockets and chain for Uneven wear patterns. Over-tightening can lead to accelerated wear on these components.
  6. Temperature Increase: An over-tightened chain can generate excessive heat. After a ride, carefully touch the chain guard or nearby components. If they feel Unusually hot, the chain might be too tight.

Evo Engines

Many Harley Davidson models fitted with the Evolution (Evo) engine have been reported to experience issues with the automatic primary chain tensioner. The Evo engine, produced from 1984 to 1999, is known for its reliability and longevity, but the primary chain tensioner has been a weak point for some owners.

Which Models Specifically?

Models such as the Touring Models, Dyna Glide Models, Softail Models, and Sportster Models equipped with the Evo engine have been reported to experience issues with the automatic primary chain tensioner.

Related articles:
> Sportster Years To Avoid
> Dyna vs Softail
> Dyna vs Sportster

Twin Cam Engines

The issue of the automatic primary chain tensioner is not just limited to the Evo engine models. Even the newer Twin Cam engine models have experienced similar problems. The Twin Cam engine, introduced in 1999, was designed to offer improved performance and power over the Evo engine.

Related article:
> Harley Twin Cam Years To Avoid

Which Models Specifically?

Various models equipped with the Twin Cam engine, including the LiveWire, Touring Models, Dyna Glide Models, Softail Models, Sportster Models, and Screamin Eagle CVO Models, have reported issues with the automatic primary chain tensioner.

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Milwaukee 8 Engines

The newest engine in the Harley Davidson lineup, the Milwaukee 8, has also been reported to have issues with the automatic primary chain tensioner. Introduced in 2017, the Milwaukee 8 engine was designed to offer improved performance, power, and fuel efficiency.

Related article: Harley 107 vs 114 – A Milwaukee-Eight Showdown

Which Models Specifically?

Models such as the Touring Models, Softail Models, and Tri Glide equipped with the Milwaukee 8 engine have been reported to experience issues with the automatic primary chain tensioner.

Related:
> Twin Cam vs Milwaukee 8
Harley’s Twin Cam vs Evo: Who Reigns Supreme? (Revealed)

What Are The Symptoms Of A Bad Primary Chain Tensioner?

If your automatic primary chain tensioner is malfunctioning, you might notice symptoms such as unusual noise from the primary chain, increased vibration, poor engine performance, or even engine failure in extreme cases.

If you notice any of these symptoms, it’s recommended to have your motorcycle inspected by a qualified technician as soon as possible.

Before moving on, it’s important to understand that Harley’s utilize a chain driven cam; whereas, some manufacturers opt for a belt driven cam. Here’s a video detailing the difference:

What Can Be Done About This?

There are several solutions available to address the issue with the automatic primary chain tensioner. Some owners opt to replace the factory-installed tensioner with an aftermarket manual tensioner, such as the Baker Attitude Adjuster or the Hayden M6. These manual tensioners can be adjusted to provide the optimal tension for the primary chain, reducing the risk of over-tightening.

For issues like overheating or power loss, start by checking the tensioner’s adjustment. Overheating can be mitigated by ensuring the bike isn’t overloaded and using a high-quality lubricant that resists heat. If the tensioner is dirty, causing noise, clean it thoroughly with a soft brush and mild soap. Regular maintenance, including lubrication and tension checks, can prevent these issues from escalating.

Example of a new automatic primary chain tensioner that's installed inside the primary case of a Harley Davidson

Is The Tensioner Adjustable?

The factory-installed automatic primary chain tensioner on Harley Davidson motorcycles is not adjustable. It is designed to automatically adjust the tension on the primary chain based on the engine’s operating conditions. If you wish to have an adjustable tensioner, you will need to replace the automatic tensioner with an aftermarket manual tensioner.

Primary Tensioner Upgrade Options

There are several upgrade options available for the primary chain tensioner. The most popular options are the Baker Attitude Adjuster and the Hayden M6 manual tensioner. These manual tensioners allow you to adjust the tension on the primary chain to your preference, reducing the risk of over-tightening.

Harley’s Reaction To These Problems Over Time

There have been several revisions to the automatic primary chain tensioner over the years. For example, the post-2010 models feature a more robust design, reducing the risk of over-tightening. So, these changes are important to keep in mind if you’re considering upgrading the chain tensioner.


How Much Does It Cost To Replace The Primary Chain Tensioner?

The cost to replace the primary chain tensioner can vary depending on the make and model of your motorcycle, the type of tensioner you choose to install, and whether you choose to do the work yourself or hire a professional. On average, you can expect to pay between $100 to $300 for an aftermarket manual tensioner, plus labor costs if you choose to have the work done by a professional.

Can You Replace The Tensioner By Yourself?

Yes, it is possible to replace the primary chain tensioner yourself if you have some mechanical knowledge and the right tools. There are numerous guides and tutorial videos available online that can walk you through the process.

However, if you’re not comfortable doing this kind of work yourself, it’s recommended to have the work done by a qualified technician.

What Happens If You Ignore The Issue? Can You?

Ignoring the issue with the automatic primary chain tensioner is not recommended. If the tensioner over-tightens the primary chain, it can lead to premature wear of the chain and bearings, reduced engine performance, and in extreme cases, catastrophic engine damage. Therefore, if you suspect an issue with your tensioner, it’s important to address it as soon as possible.

Keep reading: What Year Harleys To Avoid

Quick Overview of Important Points

To recap, the automatic primary chain tensioner on some Harley Davidson motorcycles has been reported to over-tighten the primary chain, leading to a range of issues. This problem has been reported on models with the Evo, Twin Cam, and Milwaukee 8 engines. Symptoms of a bad tensioner include unusual noise, increased vibration, poor engine performance, and engine failure. Solutions include replacing the automatic tensioner with an aftermarket manual tensioner, such as the Baker Attitude Adjuster or the Hayden M6.

What is the primary concern with Harley Davidson’s automatic primary chain tensioner?

The main issue with Harley Davidson’s automatic primary chain tensioner is its tendency to over-tighten the primary chain. This can lead to premature wear of the chain and bearings, and in severe cases, catastrophic engine damage.

Which Harley Davidson engines have reported issues with the automatic primary chain tensioner?

Problems with the automatic primary chain tensioner have been reported in the Evolution (Evo) engine, Twin Cam engine, and the Milwaukee 8 engine models.

How can I identify if my Harley’s primary chain tensioner is malfunctioning?

Symptoms of a malfunctioning tensioner include unusual noise from the primary chain, increased vibration, poor engine performance, and in extreme situations, engine failure. If any of these signs are observed, it’s advised to consult a qualified technician immediately.

Are there any alternative solutions to the factory-installed automatic primary chain tensioner?

Yes, many owners replace the factory-installed tensioner with aftermarket manual tensioners like the Baker Attitude Adjuster or the Hayden M6. These manual tensioners allow for optimal adjustment, reducing the risk of over-tightening.

Is it possible to adjust the factory-installed automatic primary chain tensioner on Harley Davidson motorcycles?

No, the factory-installed automatic primary chain tensioner is not adjustable. It’s designed to auto-adjust based on the engine’s operating conditions. For adjustable tension, one would need to opt for an aftermarket manual tensioner.


Wrapping Up

Basically, while the automatic primary chain tensioner issue can be a cause for concern, it’s important to remember that it’s not a problem that affects every Harley Davidson motorcycle. If you are experiencing symptoms, there are solutions available. Whether you choose to replace the tensioner yourself or have the work done by a professional, addressing the issue promptly can help to ensure the longevity and performance of your motorcycle.