  The new data on the elastic $pp$ and single pion production reaction $pp\to
pn \pi^{+}$ taken at the incident proton momentum 1683 MeV/c are presented. The
data on the $pp\to pn \pi^{+}$ reaction are compared with predictions from the
OPE model. To extract contributions of the leading partial waves the single
pion production data are analyzed in the framework of the event-by-event
maximum likelihood method together with the data measured earlier. The analysis
allows us to obtain the assessment with a better precision the contributions
from different initial partial waves.
