UMA THROTTLE BODY KIT R15 V3/V4/M/ MT-15/FZS V2 – 34MM

The UMA Racing Throttle Body Kit (34mm) is a high-performance induction upgrade designed to replace the stock throttle body on Yamaha’s 155cc VVA engine platform. By increasing the bore size to 34mm, it allows for a higher volume of air to enter the combustion chamber, which is essential for engines that have been modified with high-flow exhausts, larger injectors, or big-bore kits.

This kit is a staple for riders looking to maximize the mid-to-high RPM power of their R15 V3/V4, MT-15, or FZS V2.

Key Features

• Increased Bore Diameter (34mm): Provides a significant increase in airflow over the standard stock unit (typically 30mm), leading to improved throttle response and higher peak horsepower.

• Dual Injector Ready: One of the standout features of this kit is that it is dual-injector capable. This allows you to run a second injector for high-performance builds that require massive amounts of fuel at high RPMs.

• CNC Aluminum Air Funnel: Includes a precision-machined velocity stack (air funnel) that smoothes out the air intake, reducing turbulence and increasing the velocity of the air entering the engine.

• Interchangeable Intake Manifold: The kit is designed with versatility in mind, often allowing for different manifold lengths to tune the intake pulse for either torque or top-end power.

• Cast Alloy Construction: Made from high-quality cast alloy for durability and heat resistance, ensuring the unit maintains its precision even under racing conditions.

Compatibility Guide

This 34mm kit is specifically tailored for the Yamaha 155cc VVA engine family, including:

• Yamaha R15 V3 & V4 / R15M

• Yamaha MT-15

• Yamaha FZS V2 / V3

• Yamaha WR155R

Performance Insight: Why 34mm?

While UMA offers sizes from 32mm up to 42mm, the 34mm is often considered the “Sweet Spot” for Street-Racing builds.

• 32mm: Best for standard engines or light “Bolt-on” mods.

• 34mm: Best for engines with a 62mm/63mm Bore Up Kit and a performance ECU (like the UMA M5 or Juken 5).

• 36mm+: Reserved for full-race engines with heavily ported heads and high-lift camshafts.

Important Note: Installing a 34mm throttle body requires a re-map of your ECU. Without a proper tune, the engine will likely run “lean” (too much air, not enough fuel), which can cause poor performance or engine damage.

32MM vs 34MM

• 32MM:
  • Better for stock engines
  • Balanced performance
  • Easier tuning
• 34MM:
  • Best for modified engines
  • Higher airflow = more power
  • Requires proper tuning