EVO 1340 Timing Marks Explained: Gears vs. Ignition Timing

ByThe Answerlode Editorial Team

Understanding EVO 1340 Timing: Gear Alignment vs. Ignition Timing

If you’re working on a 1340 EVO engine, one of the most common points of confusion is the difference between gear timing marks and actual ignition timing. These are two separate procedures, and mixing them up can lead to frustration and wasted hours troubleshooting.

Gear Timing Marks: Getting the Valvetrain in Sync

The timing marks found on your EVO gears—on the crankshaft gear, camshaft gear, and breather gear—are strictly for mechanical synchronization. These marks must all line up together to ensure your valves operate in proper sequence with the crankshaft rotation. Think of this as the foundational setup: if your gears aren’t timed correctly, your whole engine will run poorly, regardless of ignition timing.

When setting gear marks, you’re looking for:

  • Crankshaft gear mark – Usually a simple dot or line
  • Camshaft gear mark – Lines up with the crank mark
  • Breather gear mark – Often smaller and easy to overlook, but essential for proper breather function

A useful troubleshooting tip: rotate the engine a full 360 degrees and verify the marks stay aligned. If they drift, you may have a gear indexing issue.

Ignition Timing: Setting When the Spark Fires

Once your gears are properly aligned, ignition timing is an entirely different procedure. Ignition timing refers to when the spark plug fires relative to piston position, and it’s controlled by the ignition module and verified using the crankshaft markings on the flywheel.

On the EVO, these flywheel marks are visible through a small inspection hole on the left side of the engine case (near the timing cover plug). You’ll see two reference marks:

  • TDC (Top Dead Center) Mark – Usually displayed as a vertical line; the piston is at the top of the cylinder
  • Advanced Timing Mark – Typically a dot or alternate symbol, indicating a few degrees before TDC where the spark should ideally fire

To set ignition timing statically, remove the timing inspection plug from the left side of the motor, use a timing light, and verify that your ignition fires at the correct mark specified in your bike’s manual (usually the advanced mark, but this varies by year and ignition module).

The Key Difference: In Practice

Here’s the simplest way to remember it:

  • Gear marks = mechanical synchronization of internal valve components (set once, then leave alone)
  • Ignition timing = electrical timing of when the spark fires, verified via flywheel marks visible from the left side of the motor (adjusted with your ignition module or points, if applicable)

Many EVO builders get tripped up because they set their gears perfectly, then assume the engine is timed. But a perfectly timed engine requires both: gears in sync and the ignition firing at the right moment.

Pro Tips for EVO Timing Work

  • Install a clear plastic timing hole plug after you finish your timing check—it prevents oil splatter and makes future inspections cleaner
  • Mark your ideal timing mark with a small dab of paint or marker for quick reference during adjustments
  • If you’re unsure whether your marks are correct, consult your specific model year manual; EVO timing specifications vary slightly between years
  • When in doubt, start at TDC, run the engine, and use a timing light to dial in the curve from there

With these two procedures clearly separated in your mind, timing your EVO becomes much more straightforward. Get your gears aligned first, then fine-tune your ignition timing, and you’ll have a rock-solid running engine.

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