Which Harley-Davidsons Are Compatible With The 131 Crate Engine?

Over the course of its more than 120 years of existence, Milwaukee, Wisconsin-based, manufacturer Harley-Davidson has established itself as the preeminent name in American motorcycles. The company has done so by releasing a slate of iconic Harley-Davidson bikes whose mix of hard-nosed style and unyielding power is rivaled by few in the motorcycle industry. 

With more than a century's worth of innovation behind it, the company is always looking to bolster the power and performance of its bikes, and some would argue Harley-Davidson outdid even itself when it produced its Screamin' Eagle Milwaukee-Eight 131 Crate Engine in 2020. At the time it was billed as the highest displacement engine Harley-Davidson has ever produced, but in 2023 it released a 135-cubic inch crate engine for newer bikes. Despite costing almost as much as a new bike might, the 131 Crate Engine has become an upgrade many power-hungry engine swappers are more than willing to pay for.

To be clear, there are actually three versions of the 131 Crate Engine. There are two versions for 2017 or later Touring builds — a Twin-Cooled engine and an Oil-Cooled engine – and an Oil-Cooled version built for certain 2018 and later Softail bikes. However, the engines are not compatible with every H-D build that fit their particular parameters, meaning you'll need to do some research to find out if your Harley can support a 131 upgrade. Moreover, Harley-Davidson notes such upgrades "require ECM calibration with Screamin' Eagle Pro Street Tuner or dealership installed Screamin' Eagle calibration." Even then, they are not legal in all 50 U.S. states.   

There is only one U.S. state in which the Screamin' Eagle Milwaukee-Eight 131s are not legal under any circumstance — the state of California. That's because the engines do not meet the state's vehicle emissions restrictions, which are tougher even than those set by the federal government. Given the 131's massive output, it may be a good thing that not everyone can make the upgrade. As noted in Cycle World's 2020 review, the 131 essentially transforms your Harley into a full-blown hot rod that can produce 121 horsepower and accelerate from 0-100 in just over 9 seconds. Your average rider likely cannot safely handle that kind of juice.

If you're curious which Twin-Cooled Touring bikes you can outfit with the 131, the crate engine is compatible with dozens of 2017 and later models, including several CVO builds, some Road Glide Ultras and Road Glide Limiteds, multiple Ultra Limiteds and Ultra Limited Lows, and the '23 Electra Glide Highway King. Of Harley's Oil-Cooled Touring bikes, the 131 is compatible with multiple Road Glides, Street Glides, Road Kings, and Electra Glides, including CVO models.

As for the Softails compatible with the Oil-Cooled 131, the list of bikes is too lengthy to lay out here, though several Fat Boys, Street Bobs, Low Riders, and Sport Glides can support the upgrade, among many other builds. If you're uncertain about your bike's compatibility with the 131 Crate Engine, consult your local Harley-Davidson dealer for guidance. Just know that, according to Harley-Davidson, the 131 Crate Engines will only be deemed street legal when installed on one of those compatible Harley-Davidson builds, and only after the proper emissions upgrades have been performed.