Motors like air, and the more air you can get in there, the better! If you've got at least 2k on your motor, synthetic oil will be fine. You might have to adjust your carbs a little to match the air flow. Good luck.
Do a search I have a BMC Race air filter which I also add information about my finding.Originally posted by asalandy
I've heard contradicting views regarding K&N filters. Should I get a K&N for my bike? Should I move over to synthetic?