Mikuni Large Round Main Jet #122.5 4-Pack - Harley & Indian V-Twin
About Mikuni
Mikuni has supplied carburetors and fuel-system components to the motorcycle industry for decades, and its HSR series remains a common choice for carbureted Evolution and Twin Cam V-twins where a clean, tunable fuel curve matters more than electronics.
Keep your carbureted V-twin running strong with genuine Mikuni Large Round Main Jets. This 4-pack of #122.5 jets is crucial for fine-tuning your air/fuel ratio at cruise and part-throttle, especially after modifying your intake or exhaust. Ensure your Harley or Indian motorcycle's Mikuni carburetor is precisely jetted for optimal performance.
Why riders pick this
- Genuine Mikuni OEM quality for reliable performance
- Exact #122.5 size for precise fuel calibration
- Large round style fits specific Mikuni carburetors
- 4-pack quantity for tuning flexibility or spares
- Essential for optimizing air/fuel mixture
When you're chasing every last bit of usable power from your V-twin, proper carburetor jetting is non-negotiable. These genuine Mikuni large round main jets in #122.5 size are the real deal, designed to precisely meter fuel flow and keep your engine happy across the rev range. Swapping jets is a fundamental step in dialing in your bike's performance, whether you've installed a new air cleaner, a freer-flowing exhaust, or are simply compensating for changes in altitude.
Precision Fuel Delivery
- Genuine Mikuni OEM components ensure reliable performance
- #122.5 orifice size for accurate fuel metering
- Large round body style for specific Mikuni carburetor applications
- Convenient 4-pack provides spares or options for fine-tuning
The Foundation of a Good Tune
Your main jet controls the fuel delivered during the most frequently used throttle positions. Having a selection of sizes on hand, like this 4-pack, lets you experiment and find the sweet spot for your specific V-twin setup. It’s a critical piece of the puzzle for any rider looking to get the most out of their carbureted Harley-Davidson or Indian Motorcycle.
Specifications
- Brand: Mikuni
- Manufacturer Part #: FN100604-122.5
- Quantity: 4 per pack
- Jet Size: #122.5
- Style: Large round
- Length: 4.4 in
- Width: 2.2 in
- Height: 0.6 in
- Weight: 0.05 lbs
- Country of Origin: Japan
Common questions
What does the #122.5 size mean?
The number #122.5 indicates the orifice diameter, which controls the amount of fuel delivered. Larger numbers mean a richer fuel mixture, while smaller numbers lean it out.
Will these jets fit my Harley-Davidson with a Mikuni carb?
These jets are designed for V-twin motorcycles equipped with Mikuni carburetors that use large round main jets. Always confirm your specific carburetor model and existing jet style before ordering.
Why is a 4-pack useful for tuning?
A 4-pack gives you multiple jets of the same size, allowing for spares or consistent tuning across multiple carburetors. It's also ideal for those who may need to adjust for different altitudes or conditions.
Ordering from Vtwinbikers
- Brand new, sourced through authorized US distribution — never used, never grey-market.
- Not sure it fits? Use Shop by Bike to filter by your year and model, or email us and we will confirm before you order.
- Harley-Davidson and Indian Motorcycle is all we do, so you are talking to people who ride what you ride.
| BRAND | Mikuni |
| TYPE | Jets |
| SKU | 134-71225 |
| WEIGHT | 0.05 lb |
