
This part being universal, it may require adaptations
KEIHIN MAIN JET 90 – Manufacturer reference: 99101-357-0900
Keihin main jet sized 90, designed for carburetion adjustments on Keihin carburetors. A simple and essential replacement part to restore clean engine operation when the original main jet is worn, clogged, or when adjusting the mixture for specific conditions (altitude, fuel, tuning).
The main jet directly affects the air/fuel mixture at high RPMs and during throttle openings. Its replacement is part of regular maintenance and fine-tuning of the carburetion: it allows for adjusting the mixture richness for a more responsive engine behavior without modifying other carburetor components. Suitable for Keihin carburetors that accept a size 90 jet — check compatibility with your model before installation.
Installation advice: simple installation but recommended to be performed by a mechanic or experienced DIYer. Clean the jet well, check the condition of the seals, and conduct tests in safe conditions after any carburetion adjustments.