  A parameter-free evaluation of the $N - \Delta$ electromagnetic transition
form factors is carried out in a light-front constituent quark model, based on
$N$ and $\Delta$ eigenstates of a mass operator which reproduces a large set of
hadron energy levels. A one-body electromagnetic current, including the
constituent quark form factors previously determined within the same approach
from nucleon and pion experimental data, is used. Our prediction for the
magnetic transition form factor is compared with the results both of
phenomenological analyses of experimental data for the $\Delta$
electroproduction, and of an analysis which includes the effects of
off-energy-shell $\pi - N$ final state interaction.
