The is a constant-velocity (CV) carburetor frequently used in 150cc 4-stroke engines, such as the GY6 series. It is designed to provide smooth acceleration and fuel efficiency compared to mechanical slide carburetors. Key Specifications Bore Size: 25mm inner diameter on the intake side. Outer Diameter: 34mm (intake) and 42mm (air filter side).
A rubber-tipped plunger hooked to the float tang that seals off the fuel inlet line when the bowl is full. Key Troubleshooting Checkpoints on a Patched Diagram
The lower half of the diagram details the components responsible for mixing fuel with incoming air. mikuni bs25 carburetor diagram patched
The "patched" diagram is a user-modified version of the official schematic, typically found on forums like ScooterInvasion, ADVRider, or ThumperTalk. A user takes the official JPG or PDF, opens it in Paint, Photoshop, or even a PDF editor, and patches the errors.
Moves vertically to control air inflow.
For motorcycle enthusiasts and DIY mechanics, the Mikuni BS25 is a familiar name. This 25mm diaphragm-type carburetor is a staple on many small to mid-displacement bikes, including the Yamaha YBR 125, Suzuki Intruder 125, Yamaha LC135, and even certain utility vehicles like the Yerf Dog 4x2 Scout. It's known for its reliability and good fuel economy, but keeping it in perfect running order often requires a deep dive into its inner workings. This is where a becomes an invaluable tool.
Variable venturi CV type where the vacuum-operated slide (diaphragm) controls the air-fuel mixture based on engine demand. Understanding the Carburetor Diagram The is a constant-velocity (CV) carburetor frequently used
’s workshop, but tonight, it was cut by the sharp scent of solder. Spread across his scarred wooden bench was a weathered piece of butcher paper containing the holy grail of his current project: a heavily annotated, hand-corrected schematic of a Mikuni BS25 constant velocity carburetor Go to product viewer dialog for this item.
When enthusiasts discuss finding a "," they are usually searching for a clear schematic to guide them through a rebuild, specifically looking for solutions to common pitfalls—the "patches"—that arise from repairing these older, often corroded, or modified carburetors. Outer Diameter: 34mm (intake) and 42mm (air filter side)
: True Mikuni tuning requires the pilot screw to be set at 1.5 to 2 full turns open out from seat. A patched schematic outlines the specific sequence of the spring, tiny metal washer, and rubber O-ring to prevent unmetered air from leaking past the threads. 3. Float Valve & Fuel Level Circuit Controls fuel input inside the lower float bowl. Carburetor - Mikuni BS25 Series Round Slide
The BS25 is prone to vacuum leaks at three diagram points: