Main Jet #91 for SI Carbs for Scooters & Mopeds
ITEM# TT-25756
Guarantee Safe Checkout
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
Description
Main Jet #91 for SI Carburetors in Scooters and Mopeds
This #91 main jet controls how much fuel reaches the engine in SI-style carburetors used on a range of scooters and mopeds. It is a small, cone-shaped piece that sits at the bottom of the main jet stack. Like other components listed under scooter carburetors & jets, it plays a real role in how well the engine runs. Because the jet size sets the fuel flow, it is an important part for anyone wanting to fine-tune their machine.
Understanding Jet Sizes
Main jets come in sizes from 82 to 165. Vintage Vespas generally run jets in the 85 to 116 range. Engines that have been modified for more power often need larger jets to supply the extra fuel they demand. A higher jet number lets more fuel pass through, so it can make a noticeable difference when tuning.
Adjusting Your Jetting
Getting the jetting right usually takes some testing and adjustment. Different scooters and mopeds can need different jet sizes depending on what has been changed and how they are ridden. For step-by-step jetting advice, it is worth checking a dedicated guide or blog. Adjusting the jet size can help balance the air-fuel mixture and make the ride smoother.
Specifications
- Size: 91
- Position: Main Jet
- Fits: SI-type carburetors, main jet size #91 (scooters and mopeds)
Fitment
How to choose: Pick a main jet size that suits your engine's jetting. Sizes run from 82 to 165, and the #91 is one of the sizes within that span.
Shop more: Scooter Carburetors & Jets · Scooter Parts
Reviews
