I had just turned off a main A road in semi-suburbia and had toed the old warrior into third when some unfamiliar and frankly unwelcome noises started to emanate from down below. The main din was a sort of whiney buzz. I began to picture worn splines and broken bits of cog being hurled around the box causing major damage. First gear seemed to be working ok so I limped home very very slowly and of course completely ignoring the workshop manual advice of ‘stop the engine immediately and investigate the problem’. There must be a God out there because it was just after I had actually reached home that I finally lost first gear and consequently any kind of forward propulsion at all. After a brief demo of what happens (or not) when a gear is engaged plus some observation of noises from within, mechanical guru Paul and I rolled the M20 onto the lift.
We inspected the selector mechanism and discovered that it was in fine fettle and performing its cog shifting role admirably. We also had a little look inside the gearbox and found that to be in decent health. Our next step was to remove the primary chaincase cover and have a peek at what delights awaited us there.
Low and behold, it was immediately noticeable that the retaining nut on the end of engine shock absorber was in such a state of looseness that it was apparently trying to drill its way through the chaincase cover. Said nut is now tight and M20 is once more a machine with (sort of) silky smooth gear changes. Time to get back to dug-dug-dug-dug-dugging!