Calling all Mikuni carburetor fans! This little black spring might not look like much, but it's crucial for getting your carb tuning just right. This is the genuine Mikuni needle valve arm spring specifically for their square pump carbs, part number 730-03033. The 80-gram spring rate determines your pop-off pressure - that critical point where the needle valve opens to let fuel into the engine. Different spring rates give you different pop-off pressures, and this 80-gram version is that perfect middle ground for many applications. Measuring 14.6mm in length, it's designed to fit precisely where it needs to go in your Mikuni carb setup. Whether you're rebuilding, tuning, or just doing routine maintenance, having the right spring is essential for proper fuel delivery and engine performance. These springs do wear out over time, leading to inconsistent pop-off pressure and all sorts of running issues. If your engine's been acting up - bogging down, flooding, or just not running crisp - this little $5 part could be the solution. Keep a couple spares in your toolbox because you never know when you'll need one at the worst possible moment. For Mikuni carb owners, this isn't an optional part - it's essential maintenance equipment that keeps your machine running smooth and reliable.
Free 30-day returns 
Free 30-day returns
