Summary

• The Knucklehead, an iconic Harley-Davidson mannequin, boasts nostalgic appeal and symbolizes the model’s overcome Indian Motorcycles within the Thirties.
• The modern Knucklehead engine, that includes overhead valves, marked a turning level for H-D, pushing the corporate to refine and enhance its design.
• Despite early technical points, Harley-Davidson engineers labored tirelessly to reinforce the Knucklehead, solidifying its standing as a legendary bike.

To the common individual, the phrase “Knucklehead” is used as an insult to somebody who’s both clueless or silly. But for Harley-Davidson lovers, the phrase will immediately convey an enormous smile to their faces. This is, after all, as a result of Knucklehead being one of the manufacturer’s most legendary motorcycles ever produced in its over 120-year historical past. Not solely do they conjure up some highly effective emotions of nostalgia from Thirties Americana, however in addition they function a reminder of the bike that helped prepare dinner its rival competitor, Indian, into submission.

The Knucklehead, formally often known as the 1936 E/ES/EL, was the primary Harley-Davidson to characteristic overhead valves, whose valve covers resembled the knuckles on a closed fist (therefore the identify). In manufacturing from 1936 to 1947, it’s estimated that solely 41,000 Knuckleheads have been made. Though the bike wasn’t 100% excellent upon its debut, Harley-Davidson proceeded to refine and polish the Knucklehead into the long-lasting standing that it holds right now.

In order to provide the newest and correct info doable, the information used to compile this text was sourced from numerous producer web sites and different authoritative sources, together with Harley-Davidson, Mecum, Wisconsin Historical Society, Hagerty, White Knuckler Brand, and Cycle World.

The Knucklehead Engine Put Harley-Davidson Back within the Lead

By the mid-Thirties, Harley-Davidson was already established as one of many prime bike producers in America. Both by way of its quickly rising buyer base, and authorities contracts to supply bikes for the US navy. But regardless of all that, it was nonetheless chasing the tail of its arch-rival, Indian Motorcycles.

Sales have been lagging behind, and the executives at Harley-Davidson wanted one thing to spice up gross sales and put them again within the entrance of the pack. Thus got here the Knucklehead engine–the model’s first V-Twin with overhead valves. The mission was led by engineers Hank Syvertson and Joe Petrali, who developed Harley-Davidson’s first engine with a staggering 61 cubic inches. The solely main downside the corporate confronted was that they needed to launch the engine to the general public earlier than it was utterly completed.

It Marked a Turning Point For Harley-Davidson

Like the saying goes “pressure makes diamonds.”, the identical could be mentioned for a way Harley-Davidson developed the Knucklehead engine. With Indian Motorcycles reigning over Harley within the Thirties, the corporate’s push for larger gross sales led to the conception, after which manufacturing of the Knucklehead engine. Prior to its growth, H-D bikes have been powered by the 45 cubic inch Flathead engine, which earned its identify on account of its flat-topped, vented cylinder heads.

But the stress on Harley actually set in 1930 when Indian debuted with a Big Twin engine of its personal, the 74 cubic inch mill. Then in 1936, the Knucklehead arrived on the scene, out there in two totally different displacements: 61 cubic inches and 74 cubic inches. In addition to being the primary Harley Big Twin to characteristic overhead valves, it got here outfitted with an efficient oil circulation system to maintain all of its internal workings properly lubricated.

1947 Harley-Davidson EL Knucklehead Engine

The Early Knuckleheads Had Some Technical Issues

With time and stress up in opposition to Harley-Davidson to overhaul Indian, a few of that made its method into among the early variations of the Knucklehead affected by a sequence of technical points. With solely 2,000 items produced in 1936, some points that plagued this bike included brittle valve springs, rockers that weren’t sufficiently lubricated, and frequent situations of leaking oil. Because this was the primary model of the Knucklehead engine mass-produced for the general public, its form and configuration have been additionally drastically extra advanced than its predecessor. The end result was a brand new V-Twin that had some sealing difficulties.

Harley-Davidson Engineers Made Some Much-Needed Improvements to the Newer Knuckleheads

Well conscious of the technical points hurting the primary line of Knuckleheads, Harley engineers went proper to work on fixing these issues and refining the event of the engine. Nearly redesigning it solely, the engine obtained a number of enhancements, comparable to stiffer valve springs, an improved rocker design, a bigger flywheel, and an answer for these annoying oil leaks. In addition, the corporate despatched restore kits to Harley-Davidson dealerships to restore the bikes that have been already bought and on the highway.

By 1938, Harley had ironed out all of the technical flaws however continued to enhance upon the Knucklehead’s design up till its last 12 months of manufacturing (1947). Post which, it could be replaced by its successor, the Panhead. Given that most of the components on the unique 1936 Knucklehead bikes have been made that 12 months, it’s virtually unimaginable to seek out substitute components right now. Restoration lovers will both should craft these particular components themselves or alter the same half from a separate bike to ensure that it to work.

80 Years Later, The Harley-Davidson Knucklehead Remains an Icon

Though there have been a couple of hiccups at first, the changes made to the Knucklehead helped solidify it as some of the legendary bikes ever produced by Harley-Davidson. Ask any H-D fanboys what mannequin bike they might need out of the model’s complete 120+ 12 months historical past, and the Knucklehead will be close to the top of the list. The unforgettable expertise of driving this final old-school bike, in addition to the sentiments of nostalgia that include it, remind fashionable riders of the thrills felt when this primary arrived within the mid-Thirties.

With each energy and velocity at its disposal, it’s straightforward to grasp how the Knucklehead put Harley-Davidson again within the lead and Indian in its mud. Not to say, how the Knucklehead engine grew to become grounded as the muse that every one future Big V-Twin motors have been constructed. This additionally resulted within the Milwaukee-Eights and Revolution engines that we get pleasure from right now.

1947 Harley-Davidson EL Knucklehead Specifications

Modern-Day Reverence

Many new-generation Harley-Davidson riders are enthralled by the model’s inflow of high-performance bikes such because the Sportster S, Low Rider ST, Pan America 1250, Road Glide, and Street Glide. But extra seasoned riders nonetheless specific appreciation for the historic significance behind the Knucklehead. Much in the identical method automobile guys would adore and admire a ’69 Plymouth Roadrunner.

Sure, they don’t seem to be precisely in every single place on the highway. But when one exhibits up at a bike meet, it’s unimaginable to disregard it. According to information performed by Hagerty, the Knucklehead is extra more likely to attraction to Millennials or Gen Z than an Indian Chief proprietor. They are additionally 4 out of 5 occasions extra more likely to quote a Knucklehead at a better worth than boomers. Not to say, the Knucklehead obtained a particular shout-out from actor Jason Momoa in his Harley-Davidson x On The Roam collaboration. In addition to being the dream mission for a lot of restoration lovers, the uncommon expertise of driving round on a Knucklehead is a once-in-a-lifetime alternative any Harley fan could be silly to move up.