stewgnu

yes it is lighter than a tank.
 

Update:

New wheel bearings fitted, cush stripped, cleaned, + drilled, new oil in backbox, installed rossopuro reaction rod (thanks Harry) fitted with new rose joints.
 
Clunk is gone!  C'est magnifique!
Admittedly the exact source of the problem still remains unidentified as I did everything all in one go, but I'd guess wheel bearings as per docc's original advice.
 
Added bonus in fitment of crossover-less headers (thanks Harry!) : Access to alt cover improved plus bike looks wayyy better, sounds even more rrrockin and, is it my imagination (?) but she seems to pull more strongly too!
 
Damn these bikes are fine.

Wups...  Wiggle first, ask questions later!

Cheers guys, yes no probs, she popped off easy enough.  (Got a real hesitancy to force stuff these days).
TPS read at .349v though initially... brought it to 150mv and now she run like shit low down.
Next stop manomanaction.  Only prob is my garage is below neighbours flats- ten minutes idling+revving might not endear one...

A productive morning!
GM you were spot on- I felt it spit on my leg on start up just before the issue arose yesterday.
In hindsight I'd been vaguely aware of slight pippin n poppin from the left side for a few days.  So it must've been working it's way back.
Easy fix to slacken jube clips and worked it back into place.
 
Added bonus: The re-appearance of my neutral light following switch removal, soaking in wd and frantic tapping against the bench.
 
Extra Super Bonus: A feck and a fiddle with some wiring brought the oil light back into play.
 
More Bonus: Seat latch cable slack de-slacked, so can open seat sans bad language!
 
Hey! The sun's out!  I'm off out for a ride!