Progressive Air Gap Tune Guide

This guide explains how to correct front fork bottoming out on the RCR 80V using a simple oil adjustment—no fork replacement required.

The Issue: Bottoming Out at Speed

Riders over 200 lbs (90 kg) or those riding aggressively may experience:

• A harsh mechanical clunk

• Full fork compression under braking

• Reduced front-end stability

This is known as bottoming out.

What Causes It?

At higher speeds, two forces combine:

• Brake dive from strong front braking

• Road impact compression from bumps

These forces can overwhelm the stock fork’s air gap setting, leading to:

• Reduced control under hard braking

• Instability entering corners

• Metal-on-metal impact at full compression

What to Add

Add 10 ml of 15W high-performance fork oil to each fork leg.

Required Materials

• 15W High-Performance Fork Oil

  • Recommended: Bel-Ray 15W or equivalent

• 20 ml syringe or precise measuring tool

• Clean rag

Step-by-Step Instructions

Step 1: Support the Bike

• Place the bike on a center stand or lift

• Ensure the front wheel is off the ground

• The fork must be fully extended

Step 2: Open the Top Fork Cap

1. Carefully unscrew the top fork cap.

2. Take care not to scratch the anodized finish.

3. Keep the area clean to avoid contamination.

Step 3: Add Fork Oil

1. Measure exactly 10 ml of 15W fork oil.

2. Inject or pour the oil directly into the open fork tube.

3. Repeat for the second fork leg.

Do not exceed 10 ml per leg.

Step 4: Reinstall the Fork Cap

1. Carefully reinstall the cap.

2. Torque to 20 Nm.

3. Ensure both sides are sealed properly.

Step 5: Cycle the Suspension

• Push down firmly on the handlebars several times.

• Allow the fork to cycle through compression and rebound.

This evenly distributes the new oil.

Expected Result

You should notice:

• Firmer, more planted front-end feel

• Reduced brake dive

• Improved high-speed stability

• Elimination of harsh bottom-out clunk