vf 1000 f w/ vf 1000 r motor Ticking or knocking on clutch side

ok well I just got the bike so i nothing about it.its 1984 f with 1985 R motor. there is a loud ticking or maybe knocking sound coming from clutch side I think it is behind the clutch cover not the top end. it only dose this when going a even speed like 55 or 60 mph. if i acellerate it stops and if i let off it stops. its loud at first I thought it was exaust leak but that is not the case. HELP! its a 84 vf1000 f with 85 vf 1000r motor. I can make it doit while bike is not moving but I have to quick wind the trottle a couple times and then it will only like tick twice at mid range rpm. and if I feel the clutch cover it sounds andfeel like it behind the cover I hope its not a bearing cause I know nothing of v-4z and not even sure how they got the R motor to fit in the F frame. Looks like hell to get out.