Scarry thoughts ~ bottom end rattle/s or what?

How would you describe a bottom end rattle ? (OR ~ what is this sound!)

I have a machine which is emitting a audible tapping on idle ~ which on the face of it sounds like it is coming from the primary cases !!!!!!!!!

This tapping sounds more like rocker / tappet (single) rattle but is somewhat louder than the still audible rockers.

By sticking a rod on the crankcases there is nothing to be heard ~
but at the point of the timing access plug ~ there it is distinctive, even to the point that this the only place it can be heard via a 'rod' .

The best description or comparison I would make would be my Ford EFI six cylinder which DOES have a cam follower which sometimes causes a tappet clacking on start up.

This sounds exactly the same!

(I realise that alloy cases are deceiving ~)

The engine was rebuilt some 5,ooo miles ago ...

I overhauled the primary about two weeks ago and replaced the clutch hub bearing ~ :shock:

Check the rotor. It may loose, tightens up on revs, knocks at idle.

EXCELLENT thought ~ MichaelB

And while you're in there, check the stator. I actually had a loose stator once and its symptoms were identical to what you've described.

Jason

Yes .. I am more than a little surprised I did not 'tweek' to this straight up .. well it was the day after the night before ~ 8)

The fresh oil showed distinct signs of black deposits, which I figure were caused by the loose rotor ~???? :twisted:

I had a look and tensioned up the rotor and checked the stator clearance , even removing and replacing it.

The perplexing part is the the clearance at the bottom between rotor and the stator was quite large. where as the top was minimumal ~!!! at <.007>

The stator is fairly new in fact , but the variance is of concern to me !

(More great British quality standards? )