Thanks for all the feedback.
i bought the bike -'started on it today, gearbox oil looks recent, fan cuts in and out as it should, starts first kick, engine runs well, just need to do wheel bearings, chain and sprocket, fitted new plug and new air filter element, front and rear suspension works as it should, tyres are servicable, so it will be ready to ride in an event. no more to say really,'
the bike has 2 small holes in the air box above the back wheel. i rode about 10 hours in a dusty gritty area.
the air box and carb were extreamly dirty.
On purchase i was told the knocking was piston slap and goes when hot. its got worse!
i will speak with dealer tomorrow.
i want to upgrade to something newwer. i dont need all this hassle!