Jet Keihin Pilot #45 (FCR-MX) (4/Pkt)

The Keihin #45 Pilot Jet is a genuine replacement and tuning component for Keihin FCR-MX flat-slide carburettors, supplied in a pack of four. Pilot jets govern fuel delivery at idle and through the lower throttle range, making correct selection essential for crisp off-idle response and stable idle quality.

Sourced from Keihin — the original manufacturer of FCR-MX carburettors — these jets are precision-machined to maintain consistent fuel metering. Whether restoring a carburettor to standard specification or working through a progressive jetting tune, having multiple units on hand reduces downtime between test sessions.

• Genuine Keihin pilot jet, size #45, for accurate and consistent fuel metering
• Engineered specifically for Keihin FCR-MX flat-slide carburettors
• Controls fuel delivery at idle and low throttle positions
• Pack of 4 — keep spares on hand or work through adjacent sizes in a single jetting session
• Direct OEM-specification fit; no modification required

• 4 x Keihin #45 Pilot Jets (FCR-MX)

Install finger-tight first, then snug with a correctly sized flat-blade screwdriver — overtightening can strip the threads in the carburettor body.
Use a screwdriver blade that fully seats in the jet slot; a loose fit will cam out and damage the jet head, making removal difficult.
Before fitting, visually inspect the orifice and blow through with compressed air to confirm it is clear of debris.
When tuning, change one jet size at a time and conduct test rides under consistent conditions to accurately assess each change.
If the engine has been run on stale or contaminated fuel, inspect and replace pilot jets as part of a full carburettor service — their small orifice blocks before larger jets.
Drain the float bowl before any extended period of storage to prevent fuel varnish from clogging the jet orifice.
Store unused jets in a sealed container to protect the orifice from oxidation, which can alter fuel flow characteristics.