[lobo235]

The key to making a high-revving engine live is to establish the proper main and rod bearing clearances. If the engine is to be consistently run at high revs, the bearing clearances should generally be increased. The increased clearance allows for a greater oil flow to the bearings. These clearances are set either by grinding the crank journals to the proper size, or by using special undersized bearings that provide additional clearance. We chose to use the standard bearings and turn the journals to the proper size. more

[emj]

The small end bushings were replaced with new bushings honed to a clearance of 0.0005 inches. Replacing the bushings allowed the effective length (i.e., the distance from the center of the big end to the center of the small end) of each connecting rod to be set identically. With each connecting rod having the same effective length, the piston heights were equalized, and therefore the combustion chamber volumes were more equal. Equalizing the combustion chamber volume results in a smoother running engine. Further, the top surface of the block can be milled to match the piston height, allowing the compression to be optimized for a given piston dome shape. here

[Golobulus]

The final machine work on the block consisted of reboring the cylinders to fit 0.040-inch larger pistons. SCCA Solo 11 Stock and Street Prepared rules allow this overbore, as long as the piston crown remains the original shape (i.e., no domed pistons). On the Twin Cam, a +0.040inch overbore gives a slight increase in displacement (36 cc), an increase in compression ratio of slightly less than one-quarter of a point, and restores the cylinder bore to perfectly round. more

[eugene2k]

After removing the power-head and other parts, the steering shaft is ready for disassembly for ease of cleaning and eventual cosmetic work. [links]

[praxeologist]

The PO was around many years before and following WWII. This motor chimed in with a “whopping” 22HP. The design had deviation, but largely all that changed was the color.

[courier]

The first sign of potential trouble shown by way of damage that has broken through the casting of the exhaust housing on the leg of the motor. This would take a fairly serious impact to create such damage. here

[gtwickline]

Using a flywheel puller from the local auto parts store, and three grade 8 hardened bolts, the flywheel must be removed to get to the magneto ignition. This can require considerable force to break the flywheel free from the crankshaft. An occasional "whack" with a rubber mallet on the side of the flywheel while under pressure can assist in this operation. NEVER. NEVER smack the flywheel on the top or bottom sides. as this could damage the crank or bearings! [links]

[greigmare64]

The throttle lever has Sea-mist Green. but the body and the flywheel have shades of the later Sea-horse Green. Sometimes dealers or owners would "update" the color of "last years model" to move it out of inventory when the color change with a model year. The dilemma now is paint as manufactured or as found? For me it is a no-brainer. But I'm not saying which way we'll go with the project yet! [links]

[JenniferLee]

Our "Chief of the Boat" Remy Marco Jones enjoying the quiet advances of the OMC "Super Silent" exhaust leg on a 1959 Evinrude 35hp Lark! more

[jayrod]

Sometimes bikes find owners when they meet on the showroom floor. Sometimes they meet in a dimly lit garage with an odor of oil and gasoline in the air. This Rockers life story has none of that. It’s about patience and determination that lead to its ultimate survival.

[Vorlon]

In 1899 they started making motorcycles using a sourced engine. They produced their own engine in 1901. In 1904 they started concentrating on cars, but they went broke in 1907. more

[bitcoin1234]

First the compression was checked — good news, the right cylinder reads 130 psi and the left 100!

[jadedinformatio]

William Harley’s strategy for long distance team racing against the Indians and others was to enter both overhead valve and side-valve bikes in the same race. The overhead valve bikes would set a blistering pace leaving the side-valve bikes behind but the overhead valve bikes would typically not be able to keep up the pace and as their exhaust valves melted away the side-valve bikes that had been bringing up the rear would surge ahead to victory. Bill Harley’s strategy pretty much ensured that Harley-Davidson dominated competition during that period. Thus it was that for the 1929 model year Harley-Davidson unveiled their new production engine and it was a Flathead side-valve engine. more

[nicoleblair112]

The Flathead is one of the most important early Big Twins built by Harley-Davidson, this is its story.

[x69to005]

In the wake of the Wall Street Crash later that year Harley-Davidson’s sales plummeted by more than 80% but the following year in 1930 the Harley D model was joined in the company’s product line-up by the Harley V models which had a 74 cubic inch version of that new Flathead engine, and in 1936 as the effects of the Depression were starting to stabilize Harley-Davidson introduced the Harley-Davidson UL and ULH models with an 80 cubic inch Flathead engine. Doggedly reliable though these Flathead engines were they were very bad at managing their lubricating oil. They had a gravity fed total loss oil management system so that any oil not burned up by the engine would find its way to the garage floor, or living room floor depending on where the bike was stabled. more

[jelon94]

Harley-Davidson understood this and in creating the KHK model they fitted that boringly reliable 54 cubic inch Flathead engine with a modern roller bearing crankshaft, sports cams and polished ports. Sometimes people say “You can’t make a silk purse out of a sow’s ear” and its true, you can’t. But you can make a really nice pigskin leather purse out of a sow’s ear. And that’s just the sort of thinking that Harley-Davidson implemented in turning that “sow’s ear” old school side-valve Flathead engine into a very nice sports bike that, unlike many sports bikes, would be boringly reliable for mile upon mile upon mile. The KHK Sports model with its Flathead engine was eventually replaced in 1957 by the Harley-Davidson XL Sportster with its Ironhead overhead valve engine. But the Flathead engine had not been entirely replaced, just the top part. [links]