Brands Guides About
PROX 99101-357 Keihin Hex Main Jet 160 XR400R — main product image
PROX 99101-357 Keihin Hex Main Jet 160 XR400R
PROX 99101-357 Keihin Hex Main Jet 160 XR400R
PROX 99101-357 Keihin Hex Main Jet 160 XR400R
PROX 99101-357 Keihin Hex Main Jet 160 XR400R
PROX

PROX 99101-357 Keihin Hex Main Jet 160 XR400R

★★★★★5.0 (2 reviews)

A precision-machined #160 Keihin hex main jet for dialing in the air-fuel mixture on your Honda XR400R.

$15.78*
✓ In Stock on Amazon.com
View on Amazon

*Price sourced from Amazon.com. Last updated:Jul 14, 2026.Price and availability are subject to change.

Affiliate Disclosure: Studio Supplies may earn a commission from qualifying purchases made through links on this page, at no additional cost to you. This helps support our editorial team.

Notice a mistake? Let Us Know

Overview

The Pro X 99101-357 Keihin Hex Main Jet #160 is an aftermarket carburetor jet designed for Honda XR400R motorcycles produced between 1996 and 2004. Main jets control fuel flow at wide-open throttle, and selecting the right size is essential for maintaining proper air-fuel ratios under varying conditions. A #160 jet delivers a specific fuel volume calibrated for certain combinations of altitude, ambient temperature, and engine tune — riders commonly swap main jets when moving between elevations or after making performance modifications such as exhaust or intake changes.

This Pro X jet is machined to replicate the dimensions and flow characteristics of the OEM Keihin 99101-357 series hex main jets. The hex head design allows for straightforward installation and removal using a standard wrench or socket, without requiring specialized carburetor tools. As an aftermarket part, it provides a cost-effective alternative to factory Keihin jets while maintaining the fitment and metering accuracy needed for reliable engine performance. Note that this product cannot be sold to residents of California due to state emissions regulations governing carburetor modifications.

Key Features

This product cannot be sold to residents in the state of California.

High quality aftermarket jets for Keihin carburetors.

Specifications

Brand
Pro X
Part Number
99101-357
Type
Keihin Hex Main Jet
Jet Size
160
Compatibility
Honda XR400R (1996–2004)
Carburetor Type
Keihin

Pros & Cons

👍 Pros

  • Precision-machined to match OEM Keihin hex main jet dimensions for a reliable fit
  • Affordable aftermarket alternative to genuine Keihin jets
  • Allows fine-tuning of the fuel mixture for altitude, temperature, or engine modifications
  • Hex-style head allows easy installation and removal with standard tools

👎 Cons

  • Cannot be sold or shipped to California due to CARB emissions restrictions
  • Only fits Keihin carburetors with the 99101-357 series jet size — not universal across all Keihin models
  • Single jet included, so tuning across a range of conditions requires purchasing multiple sizes separately
  • Aftermarket tolerances may vary slightly from OEM Keihin jets

Frequently Asked Questions

The Pro X 99101-357 #160 main jet is designed for Honda XR400R models from 1996 through 2004 that use Keihin carburetors.
This is a size 160 main jet. Selecting the correct jet size depends on your altitude, temperature, and any engine modifications, so consult a jetting chart for your specific riding conditions.
It is a high-quality aftermarket replacement manufactured by Pro X. It is machined to match OEM Keihin hex main jet specifications for a proper fit in the carburetor.
This jet is restricted from sale in California due to the state's emissions regulations (CARB compliance). Changing carburetor jetting can alter exhaust emissions, which conflicts with California law for street-registered vehicles.

Related Products