Main Jet (#99) for SI Carbs for Scooters & Mopeds
ITEM# TT-26054
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Description
Main Jet (#99) for Scooters and Mopeds
The main jet sits in the lower section of the jet assembly and is shaped like a cone. It controls how much fuel passes through the carburetor, which has a major effect on how the engine runs. The #99 jet suits a range of scooter and moped models, especially classic Vespas. It belongs to the group of scooter carburetors & jets, so it plays a key role in fine-tuning fuel delivery for better performance.
Choosing a Jet Size
Main jets come in sizes from 82 up to 165. The best choice depends on any engine modifications you have made and what you want the engine to do. Vintage Vespas typically run jets between 85 and 116, while engines that have been modified may need larger jets to allow more fuel through. Many riders find the ideal size by trying a few options and comparing results.
Signs It's Time for a New Main Jet
A new main jet is often fitted when fuel delivery needs adjusting for better performance, or while an older model is being restored. If the engine responds differently or fuel economy changes, it could be worth checking the main jet size. Testing and tuning on a regular basis helps keep the engine performing well and running reliably.
Specifications
- Size: #99
- Position: Lower part of the jet assembly
- Fits: SI carburetors for scooters and mopeds; main jet, size #99
Fitment
How to choose: Compare the number stamped on the jet with the size your engine requires. This part is sized #99, and the full range runs from 82 to 165.
Shop more: Scooter Carburetors & Jets · Scooter Parts
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