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Product details
This EMPI 1.30 main jet (43-5305-0) meters fuel into the main circuit of 40/44 HPMX, 40/44/48 IDF, EPC 48/51, 48 IDA, and DCO/DCOE carburetors, and it is the main jet EMPI installs in its 40mm HPMX for dual-carb setups (47-1010-0). That carb ships with 130 mains, 170 air correctors, F11 emulsion tubes, 28mm venturis, and 52 idle jets. Order it to replace a lost or damaged stock jet.
The main jet and air corrector share the job of high-speed fueling. A larger main richens the whole main circuit, and a larger air corrector leans mainly the top end. If the midrange is right but the engine goes lean or rich near the top, change the air corrector and leave the 1.30 alone. EMPI's air correction jets for these carbs run from 1.00 to 2.20 (43-5401 through 43-5425).
Technical Details
- Manufacturer: EMPI
- Manufacturer part number: 43-5305-0
- Jet type: main jet
- Size: 1.30 mm
- Carburetors: 40/44 HPMX, 40/44/48 IDF, EPC 48/51, 48 IDA, and DCO/DCOE
- Sold as: each
Fitment & Compatibility
EMPI specifies this jet for 40/44 HPMX, 40/44/48 IDF, EPC 48/51, 48 IDA, and DCO/DCOE carburetors. Weber DGV, DFV, and ICT carbs use a different EMPI series.
Installation & Tuning Notes
Popping under load means lean. A larger main jet or a smaller air corrector adds fuel, and the rpm where it happens tells you which to try first.
Common Questions
Is 1.30 the stock main jet in an EMPI 40 HPMX?
In the dual-carb version, yes. EMPI lists 130 mains for the 47-1010-0, while the single-carb 40 HPMX ships with 135s.
Should I change the main jet or the air corrector?
If the problem shows up in the midrange, work on the main jet. If it appears only near the top of the rev range, change the air corrector first.
