
This part being universal, it may require adaptations
Dell'Orto VHST 40 Idle Jet (Manufacturer Ref: 16690_40) — a spare part dedicated to the carburation of Dell'Orto VHST 40 carburetors. This idle jet affects the distribution of the air/fuel mixture at low throttle openings, where the precision of the jet directly influences idle stability and response to small throttle inputs.
A useful part for riders who manually adjust their carburation: replacing or changing the idle jet allows for adjusting the richness at idle and fine-tuning after engine or intake modifications. Before installation, ensure that the jet and the bowl are clean; cleaning the idle passage prevents misfires. Simple installation for those familiar with the disassembly procedure of the VHST carburetor.
Keeping a handful of jets in different sizes is a good practice for testing on the bench or on the road. This original Dell Orto part fits within the maintenance and adjustment logic of carburation to achieve stable idle and consistent engine behavior at low RPM.