🔧 Jetting Finder
Select your carburetor, build level, altitude, and temperature to get a recommended starting jet.
▸ RECOMMENDED JETTING
Main Jet Size Reference Chart
| Carburetor | Build Level | Sea Level | 2,000 ft | 4,000 ft | 6,000 ft | 8,000 ft |
|---|---|---|---|---|---|---|
| OEM 22mm | Stock | 111–115 | 108–112 | 105–109 | 102–106 | 99–103 |
| Mild | 115–120 | 112–117 | 109–114 | 106–111 | 103–108 | |
| Stage 1 | 120–125 | 117–122 | 114–119 | 111–116 | 108–113 | |
| Stage 2+ | 124–130 | 121–127 | 118–124 | 115–121 | 112–118 | |
| PZ26 (26mm) | Mild | 120–125 | 117–122 | 114–119 | 111–116 | 108–113 |
| Stage 1 | 125–130 | 122–127 | 119–124 | 116–121 | 113–118 | |
| Stage 2+ | 130–138 | 127–135 | 124–132 | 121–129 | 118–126 | |
| PZ28 (28mm) | Stage 1 | 132–140 | 129–137 | 126–134 | 123–131 | 120–128 |
| Stage 2+ | 140–152 | 137–149 | 134–146 | 131–143 | 128–140 |
Needle, Pilot & Air-Fuel Screw Settings
| Carburetor | Build Level | Pilot Jet | Needle Clip | A/F Screw (turns out) | Notes |
|---|---|---|---|---|---|
| OEM 22mm | Stock | #40 | Pos 3 (mid) | 1.5 – 2.0 | Verify pilot jet — leave stock unless idle is rough |
| OEM 22mm | Mild | #42 | Pos 3 – 4 | 1.5 – 2.5 | Re-jet after adding filter + exhaust; lean at WOT otherwise |
| OEM 22mm | Stage 1 | #45 | Pos 3 – 4 | 2.0 – 2.5 | Ensure billet flywheel + rod installed before high-RPM runs |
| OEM 22mm | Stage 2+ | #45 – #48 | Pos 4 – 5 | 2.0 – 3.0 | OEM carb limits Stage 2+ — upgrade to PZ26 or PZ28 |
| PZ26 | Mild | #42 – #45 | Clip 3 (mid) | 1.5 – 2.5 | Good airflow upgrade; may need intake manifold adapter |
| PZ26 | Stage 1 | #45 – #48 | Clip 3 – 4 | 2.0 – 2.5 | Best value carb for governor-removed 224 builds |
| PZ26 | Stage 2+ | #48 – #52 | Clip 4 – 5 | 2.0 – 3.0 | Full tune-up required; multiple plug chops recommended |
| PZ28 | Stage 1 | #45 – #48 | Clip 3 | 2.0 – 2.5 | Use PZ28 only with ported head; overkill on mild builds |
| PZ28 | Stage 2+ | #48 – #52 | Clip 3 – 4 | 2.0 – 3.0 | Full build only — pairs with cam, ported head, forged piston |
Altitude Correction Quick Reference
Thinner air at altitude = leaner mixture. Drop jet size by approximately the amount shown below from your sea-level baseline.
| Altitude Band | Approx. Jet Correction | Air Density vs. Sea Level | Tip |
|---|---|---|---|
| Sea Level – 1,000 ft | Baseline (no change) | 100% | Sea-level jet is your reference point |
| 1,001 – 2,000 ft | –2 to –3 sizes | ~97% | Minor correction; most skip this band |
| 2,001 – 4,000 ft | –4 to –6 sizes | ~93% | Noticeably richer — correction required |
| 4,001 – 6,000 ft | –6 to –9 sizes | ~87% | Significant correction; re-tune A/F screw too |
| 6,001 – 8,000 ft | –9 to –12 sizes | ~81% | Full retune; consider needle clip adjustment too |
| > 8,000 ft | –12 to –16+ sizes | <78% | Full retune recommended; stock power drops 20%+ |
Temperature also affects mixture: add ~2–3 jet sizes for cold weather (<45°F), subtract 2–3 for heat (>90°F).
Carburetor Quick Guide
OEM 22mm Carb
Stock & Mild Builds
- Bore Size ~22mm
- Stock Main Jet #110–#112
- Pilot Jet #40
- A/F Screw 1.5 turns out
- Best For Stock, Mild builds
- Note Not a GX200 clone carb
PZ26 (26mm)
Best Stage 1–2 Upgrade
- Bore Size 26mm
- Typical Main Jet #122–#138
- Pilot Jet #42–#52
- A/F Screw 1.5–2.5 turns
- Best For Stage 1–2 builds
- Note May need intake adapter
PZ28 (28mm)
Full-Send Stage 2+ Builds
- Bore Size 28mm
- Typical Main Jet #132–#152
- Pilot Jet #45–#52
- A/F Screw 2.0–3.0 turns
- Best For Stage 2+, ported head
- Note Overkill for mild builds
Lean vs. Rich Symptoms
🔴 RUNNING LEAN (jet too small)
- Engine overheats quickly
- Flat or hesitant acceleration
- Popping / backfire on deceleration
- Engine surges at steady throttle
- White or light grey spark plug tip
- Loss of power, especially at WOT
- Piston / valve damage risk if ignored
FIX → Install a larger main jet (go up 2–4 sizes and retest)
🔵 RUNNING RICH (jet too large)
- Black smoke from exhaust
- Wet, black, or sooty spark plug
- Sluggish low-end, poor throttle response
- Fuel smell at exhaust
- Fouled spark plug; hard to restart
- Engine loading up or blubbering at WOT
- Increased fuel consumption
FIX → Install a smaller main jet (go down 2–4 sizes and retest)
Jetting Tips & Best Practices
Plug Chop Method
Most reliable jetting check: run the engine hard at WOT for 10–15 seconds, instantly cut the ignition, and coast to a stop. Pull the plug — tan/light brown = correct, white = lean, black = rich. Always read it before the engine cools.
One Change at a Time
Never change main jet, pilot, and needle all at once. Start with the main jet for WOT behavior. Then dial in the needle clip for midrange. Lastly, adjust the pilot/A-F screw for idle and off-idle response.
Temperature & Humidity
Cold dense air acts like lower altitude — go up 2–3 jet sizes below 45°F. High humidity also affects tune. Hot weather (90°F+) requires going down 2–3 sizes. Re-jet when seasons change significantly.
Ethanol Fuel Factor
E10 gasoline (10% ethanol) runs leaner than pure gasoline. If switching to non-ethanol or E0 pump gas, you may need to go up 2–3 jet sizes. Always note your fuel type when recording a tune.
A/F Screw Baseline
Gently seat the A/F screw (don't force it), then back out 1.5 turns as a starting point. Adjust in 1/4-turn increments at idle — out = richer at idle, in = leaner. Target the highest, smoothest idle speed.
224 Parts ≠ 212 Parts
The 224 is not a GX200 clone. Jet numbers for the 212 do not apply to the 224. The 224's larger 70mm bore and higher displacement mean larger stock jets and different carb baselines throughout. Always use a 224-specific chart.
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