Dellorto VHSB Venturi Insert
By end of 2005 (to improve the idle and respond of the carburetor) the calibration of the carburetor has been changed in the following way.
Outer idle jet: size 30 to 60
Inner idle jet: size 30 to 60
Floats: 5.2 gr. to 3.6 gr.
At the same time also the carburetor insert has been changed from
12.5 to 8.5
The figure 12.5 or 8.5 is an indication for the size of the bypass hole just after the
venturi (see arrow).
As both carburetor inserts (12.5 and 8.5) have been originally supplied with the engine, both carburetor inserts are legal to be used in the ROTAX MAX Challenge.
The actual serial production carburetor is equipped with a 8.5 carburettor insert. As we receive an ongoing demand for carburettors with insert 12.5, we have decided to offer a carburetor insert kit to enable an exchange from carburetor insert 8.5 to carburettor insert 12.5.
The exchange of the carburetor insert kit may be just executed by a trained ROTAX service center/dealer.
ROTAX MAX Challenge
The carburetor insert will become part of the technical regulation for the RMC 2010. Both versions of the carburetor inserts (12.5 and 8.5) will be legal to be used.