F2 vibration

[sohc bob]

hi after finally acquiring a 1978 cb750 F2 I noticed that when ridden there was a harshness around the 5000 rpm mark, that was felt through the bum and foot rests, on inspection I found that although well lubed many of the links in the chain where seized in an up or down position I replaced the chain and sprockets and this has made a vast improvement but ive noticed that if you venture around the 5000 rpm or above mark you lose the smoothness of the lower rev range and there is a buzzing from the foot pegs, nothing major but all the same its not there below these revs, so ... is this normal for a 78 F2, mileage is 25000 

bob

[hairygit]

It's normal on all C.B.750's I've ever ridden, and is just the way they are! Mirrors vibrate and blur as well, which is a pain, as in top gear you are over the national speed limit at those revs. One way of dealing with it is to raise the gearing slightly, say 3 teeth smaller back sprocket, because after a while at motorway speeds your fingertips start to get pins and needles!

[sohc bob]

hi hairy git, thanks for the reply, that's a relief if they are all prone to that, i was hoping it would be a feature of the bike and nothing sinister such as shot mains or crank

bob