naturally I considered faulty wiring/connections and tested everything; no sooner had I wrapped it all up and surrounded it with self-amalgamating tape , it started playing up. there are no bad connections , all of which are taken from the back of the rev counter so I would expect the rev counter or other displays to faulter if there were wiring issues - which they do not.
must be a knackered unit. It didnt work when I got the bike and I had to reprogram it.
just another problem to add to the growing list.