I read a fix (on this site, years ago) for when the speedo glass rattles in it's housing, but my searches haven't located it.
Anyone know the thread ? or have a solution without taking the housing apart. :)
If the glass rattles the speedo is no longer waterproof, you are going to have to at least remove it and examine how it was put together, I know they can be dismantled because mine has an indian dial in mph whereas my odometer is in kilometers.
John.