Harley-Davidson Fat Boy Grey Ghost 1990 Vs. 2025: How The Motorcycle Has Changed

It has been 35 years since Harley-Davidson debuted the classic Fat Boy. With its sturdy design, this powerful chopper has captured many bikers' hearts, creating a cultural phenomenon that's still going strong today. Even now, when discussing all the fantastic bikes that Harley-Davidson has released over the decades, it's hard not to mention the Fat Boy, which has some differences compared to the Fat Bob, due to the significant impact it has had not only on Harley as a corporation but on the motorcycle community as a whole. 

It is only right, then, that Harley-Davidson is offering a limited edition 2025 Fat Boy that pays tribute to the original 1990 model. This 2025 variant is called the Grey Ghost, the name the original motorcycle was known by back in the day. But, what exactly has changed between the two bikes?

Actually, it's a fair bit. For starters, the 1990 Fat Boy came with a rigid-mounted Evolution V-Twin engine capable of producing 67 horsepower. By contrast, the 2025 Grey Ghost features a Milwaukee-Eight 117 Custom rated at about 101 horsepower. The 2025 model features several improvements to technology, design, and construction that enhance its distinctiveness, including full LED lighting and anti-lock brakes, to name a few. Let's review these changes to see how Harley has adapted the Fat Boy for this day and age.

The original Fat Boy came in one color, a fine silver metallic. Couple this with the motorcycle's minimalist composition, and it becomes clear why it ended up with the Grey Ghost name. Fast forward three and a half decades, and the 2025 Grey Ghost comes in a silver and yellow that seems to be a callback to the original, but with a mirror-like finish thanks to the physical vapor deposition, or PVD process. Additionally, the new Fat Boy will feature a full LED lighting system, which will cover everything from its tail and headlights, to its turn signals.

There are several other technological improvements on the 2025 Grey Ghost. The first is the straight-line and cornering anti-lock brake system, which prevents the wheels from locking or slipping during emergency or standard braking or when cornering, respectively. 

Harley also includes a straight-line and cornering traction control system, which enhances overall control by preventing the rear wheel from spinning out when accelerating in a straight line or cornering. Alongside these systems is a straight-line and cornering drag-torque slip control, which reduces rear-wheel locking while throttling down on slippery roads. Lastly, the 2025 Grey Ghost features the company's tire pressure monitoring system. 

For the past century, Harley-Davidson has released some truly iconic engines, from the esteemed Knucklehead, Panhead, and Shovelhead to the Revolution motor that powers both the Harley-Davidson Nightster and Nightster Special. For the 2025 Grey Ghost, the company has incorporated the same Milwaukee-Eight 117 Custom engine found in the 2025 Fat Boy. 

This engine has a few improvements to help it leave a mark in the impressive catalog of motors already existing in Harley's lineup, including lightweight mufflers that give the bike a beastly sound and improved cylinder heads for better performance and fuel economy.

Other changes to the 2025 Grey Ghost include enhanced suspension for comfort, and rider modes that feature road, rain, and sport, adapting the bike to the rider's preferences, a multi-function LCD digital display, and, of course, that trusty USB-C power port.