Timing not in synch when midi synching with external hardware

I have some bass and drum lines on my trusty old Yamaha QY700 sequencer that I want to record onto a midi track in Sonar,but there's discrepancies in timing when midi synching- (sonar appears to run fractionally faster)-and thus my sequenced tracks are out of alignment.Everything is in synch for the first 20 or so bars(measures),but then timing starts to drift.
I have Sonar as master.(I haven't been able to figure out Sonar as slave)
Can latency issues affect midi?
Could real-time quantize help?
Thanks in advance.