"Dave Liquorice" wrote
But that sounds like fuel starvation. Is the breather hole in the tank
clear? Does it run with the cap loose? Is the fuel filter clear? Time to
dismantle inspect the tank/carb/gaskets. As it did run well before do not
be tempted to adjust any of the jets or poke anything through orfices.
Backwards washing with clean fuel or a gentle blast of compressed air
should clear any miniscule spots of gunk.

I'll second that, usually it's quite simple to cure. Either there is a bleed
tap on the bottom of the carb to let any accumulated muck out (is that just
Honda?) or you need to take the carb off the engine, take it apart and clean
it out (usually two or three screws). Old stale petrol in the tank is
probably the cause although it may be rust from inside the tank mucking
things up.
Make sure you do this in the open and away from any possible ignition
source.
--
Regards. Bob Hobden.
Posted to this Newsgroup from the W of London, UK