Rebuilding a Top End for the Rebuild Your Own Motor Deal

Published on May 31, 2024
Duration: 10:36

This guide details critical steps for rebuilding Harley-Davidson Evolution engines, focusing on common pitfalls. It covers correctly installing cam covers by matching pinion shaft bushings to the correct model year to ensure proper oiling of connecting rods. The guide also provides detailed instructions on bleeding and adjusting hydraulic lifters, emphasizing the importance of an oil-free lifter for accurate adjustment and preventing valve damage. Additionally, it addresses spark plug selection for dual-plugged engines and correct head gasket and piston orientation for Sportsters.

Quick Summary

When rebuilding Harley-Davidson Evolution engines, ensure correct pinion shaft bushing and cam cover matching to prevent oil starvation in connecting rods. Hydraulic lifters must be bled completely until 'hard as a rock' before adjustment to avoid bent valves. For dual-plugged Evolution engines, use J12Y short reach spark plugs.

Chapters

  1. 00:00Introduction & Engine Rebuild Overview
  2. 00:37Cam Cover & Pinion Shaft Bushing Importance
  3. 01:41Adjusting Hydraulic Lifters: The Right Way
  4. 03:59Evolution Hydraulic Lifter Adjustment Specifics
  5. 05:08Dual Spark Plug Selection
  6. 05:51Sportster Head Gasket & Piston Orientation
  7. 06:57Setting Ignition Timing Without Flywheel Marks
  8. 08:43Points Advance Setup & Adjustment
  9. 09:52Common Problems & Final Advice

Frequently Asked Questions

What is a common mistake when installing Harley-Davidson Evolution cam covers?

A frequent error is mismatching cam covers and pinion shaft bushings between early and late model Harley-Davidson Evolution engines. This can prevent proper oiling of connecting rods, leading to engine seizure.

How should hydraulic lifters be adjusted for optimal performance in a Harley-Davidson engine rebuild?

Hydraulic lifters must be completely bled of oil until they are 'hard as a rock' before adjustment. Then, they are adjusted until they spin freely with no up-and-down play, similar to solid lifters.

What spark plug is recommended for dual-plugged Harley-Davidson Evolution engines?

For dual spark plugs in Harley-Davidson Evolution engines, it is recommended to use a J12Y short reach 3/8 Champion spark plug. Using longer reach plugs can cause piston interference.

How can ignition timing be set on a Harley-Davidson engine without using flywheel marks?

Ignition timing can be set by placing a ruler in the spark plug hole and turning the engine until the piston is 7/16 inch (0.437 inches) before Top Dead Center, confirmed when both front pushrods are free to spin.

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