Topic: Third and Fourth Gear Whine

[jaytee-nz]

I have a 1974 CB750 that is stock standard. However it does whine in third and fourth gears only. It's not really bad but is noticeable compared to the other three gears.
The bike shifts fine and has no other gearbox problems. It's travelled about 35,000 miles.

I assume it's wear on the gears themselves. If so, will they wear further quickly or is it something I can worry about in 10,000 miles time ?

[scottly]

Make sure your drive chain is properly adjusted, in good condition, and well lubricated.

[jaytee-nz]

The drive chain is properly adjusted. If it only whines in two gears I'm not sure how a slack chain could be the cause ?

[Don R]

 I'd keep an eye on the oil sump and filter, maybe put in a magnetic drain plug in case something begins to flake or wear excessively. 
 Sometimes you can find a spare transmission on ebay, I bought one just in case and got lucky enough to have it back cut in trade for parts I had. It's sitting in the box waiting.

[70CB750]

On both bikes I always found the 3rd to have different sound, I dont think you have a problem, it is just nature of the beast. 

[Henning]

My third gear whines a bit when cold, but isn't noticeable when hot. It also seems to whine less with more mileage. Maybe you just need to put some miles on it and see how it pans out.