Navigating Dragonman's Motorcycle Machine Shop

Published on February 11, 2026
Duration: 7:27

This guide details advanced engine rebuilding techniques for Harley-Davidson motorcycles, as demonstrated by Mel Bernstein (Dragonman), a master machinist with 59 years of experience. It covers precision machining processes for cylinders, flywheels, valves, and bearings, emphasizing tight tolerances and quality components for optimal engine performance and longevity. The techniques shown are suitable for experienced mechanics and gunsmiths working on vintage and modern V-twin engines.

Quick Summary

Dragonman's machine shop offers expert Harley-Davidson engine rebuilding, featuring precision cylinder boring to 3.880 inches, honing to 0.0015-0.002 inch tolerances, and flywheel shaving (2.0-2.5 lbs reduction) using specialized equipment like Quick-Way borers and LeBlond lathes for enhanced performance and durability.

Chapters

  1. 00:00Introduction to Motorcycle Machining
  2. 00:16Connecting Rod & Mandrel Work
  3. 00:41Bearing Race Machining
  4. 00:58Cylinder Honing Process
  5. 01:51Valve & Guide Machining
  6. 02:15Boring & Press Work
  7. 04:27Flywheel Shaving
  8. 06:05Head Restoration & Materials

Frequently Asked Questions

What are the key machining services offered at Dragonman's shop for Harley-Davidson engines?

Dragonman's shop specializes in comprehensive Harley-Davidson engine rebuilding, including precision cylinder boring to 3.880 inches, honing with tight tolerances (0.0015-0.002 inches), flywheel shaving to reduce weight by 2-2.5 lbs, valve grinding, and valve seat replacement using nickel alloy.

What specific machinery does Dragonman use for engine rebuilding?

Dragonman utilizes specialized machinery such as a Quick-Way boring machine, a Sunnen BP10 press, a LeBlond lathe for flywheel work, and an automatic stroker machine for cylinder honing. He also employs a wide array of mandrels for precision work.

How does Dragonman ensure the longevity and performance of rebuilt Harley engines?

He ensures longevity by emphasizing the use of high-quality, non-imported parts, maintaining extremely tight tolerances (e.g., 1.5-2 thousandths clearance in honing), and addressing issues like pitted valve seats with durable nickel alloy replacements and stainless steel valves.

What is the significance of flywheel shaving in engine performance?

Shaving Harley-Davidson flywheels to reduce their weight by 2.0 to 2.5 pounds enhances engine responsiveness. This modification allows the engine to rev up and down more quickly, improving overall performance feel without sacrificing necessary durability.

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