Mikuni VM400225 Aluminum Throttle Valve Slide for VM40/VM44 Spigot Carburetors - 2.5 Cutaway, LH Idle

The Mikuni VM400225 is a genuine OEM-replacement aluminum throttle valve (slide) designed for Mikuni VM Series round slide carburetors. Compatible with VM40 and VM44 spigot-mounted carburetors, this slide features a left-hand (LH) idle screw position and a 2.5 cutaway size, making it a precise tuning component for achieving the correct air-fuel mixture at low-to-mid throttle positions.

The throttle valve plays a critical role in carburetor performance. It governs the air-fuel mixture ratio from approximately 1/8 to 1/2 throttle, with its greatest effect felt around the 1/4 throttle position. The cutaway size directly influences mixture richness: a 2.5 cutaway provides a balanced mid-range mixture, leaner than a 2.0 and richer than a 3.0 slide.

Key Features:

• Material: Anodized aluminum construction — suitable for cold weather and snowmobile applications where aluminum slides are preferred over brass
• Cutaway Size: 2.5 — provides a balanced air-fuel mixture in the 1/8 to 1/2 throttle range
• Idle Screw Position: Left-hand (LH)
• Compatibility: Fits most Mikuni VM40 and VM44 spigot-mounted carburetors with left-side idle adjustment
• Genuine Mikuni replacement part for accurate fit and reliable performance

This throttle valve is sold individually and is ideal for restoring a worn slide or fine-tuning carburetor jetting. When upgrading or replacing your slide, always match the cutaway size to your engine's tuning needs — a smaller cutaway enriches the mixture, while a larger cutaway leans it out.