  We study the decays Bu -> l nu and Bc -> l nu in the context of the Minimal
Supersymmetric Standard Model (MSSM) with explicit R parity violation. We
analyse the correlation between the two decays and show that branching ratios
(BRs) for Bc -> l nu may be of order 5% (over 40% in one case), without
violating current bounds on Bu -> l nu. Although Bc mesons are inaccessible at
the e+e- B factories, such large BRs for Bc -> l nu would possibly be within
experimental observability at LEP and the Tevatron Run II, with much larger
yields expected at the hadronic B factories. We also update some earlier bounds
on products of R parity violating couplings in the light of new experimental
results.
