hello , i would like to know if rs1600i camshaft can run with twin weber 40 ?

i have a rs1600i head complete with twin 40 weber on rebuilt block , and it is impossible to run higher 6000 rpm on 1/2/3 gear , and 4500/5000 rpm on 4/5 gear

the carbs are good and i try many possibility jetting

so , know i think perhaps the camshaft can't run with twin carbs ... ?

somebody has to try rs1600i camshaft with twin 40 ?