CARBURETOR TUNING KIT BGM FOR DELL'ORTO PHBH28 / PHBH30
Tuning kit for the classic Dell'Orto PHBH series or its replicas (YSN)
SCOPE OF SUPPLY
Main jets: 130,135
Secondary jets: 58,60
Mixing tube: AS266
Needles: X3, X7, X13
The set offers a very good basic tuning for almost all tuned Vespa engines.
MAIN JET
The main jet settles at around 130-135 for most engine setups. Only rotary valve-controlled Vespa engines usually run significantly leaner (120-125).
SIDEJET
The side jet tends to be used in the 55 range for Vespas. This is usually part of the basic setup of PHBH carburetors, so it is not included in this set.
NEEDLE
The X2 needle is often used in the Vespa range, but this is fitted ex works in 90% of all PHBHs, so it is not included in this set.
The X7 and X13 needles are variants of the X2 needle. The X3 needle has also proven to be a very good all-round needle.
MIXING TUBE
The PHBH carburetors are adapted to their intended use (2-stroke or 4-stroke) via the mixing tube. Type AV is often used for 2-strokes. However, this often tends to grease the engines with a short slide stroke. The (shorter) AS type runs much better here.
With this set you are able to provide a very good basic setup for your engine.