Noisy Gearbox

[phil1]

Hi all Mark friends, I have an issue  when I increase the speed on my Mark V to around 50mph plus the the gearbox seems noticeably noisy with a high pitched howl. Apart from that the bike is running well with no other problems. Any suggestions that can remedy this would be appreciated. Many thanks Phil.

[EW-Ron]

Without knowing these in the slightest, the 1st step with any issue like this is
to drain the gearbox oil, and inspect closely the quantity drained and if there
is any metal suspended in the oil.
Waving a magnet through the oil may be instructive too.

But you have probably already tried changing the oil, right ??
Cheers !

[eddie]

Phil,
       If the howl only occurs in the indirect gears, it is probably coming from the input gear and it's mate on the layshaft. If the howl is also evident in top gear, try adjusting the number of shims between the final drive and the main case (it will be a case of trial and error as Douglas never gave any instructions on checking this). Also, with the final drive removed, check that the large nut that secures the bevel gear on the shaft is tight - it's not a good set up as the thread is on the splined part of the shaft. If it is loose, check the spacer between the bevel gear and the bearing - any wear here will affect the mesh of the final drive.

  Regards,
               Eddie.

[phil1]

Hi Thanks for the responses. It is in top gear that has the most noise, so I will try and re adjust the bevel gear mesh with those brass shims, as you suggested Eddie. Thanks again. Phil.