Let's hope the bike you select isn't the lemon of the year, but even lemons can recover. Mr TTR is showing us how to suss a lemon on another thread.
When you say the exhaust blows whitish grey smoke - does it blow as long as the engine runs or only on starting?
As you say that it's sometimes hard to start on the starter these symptoms point to carburettor problems.
It may be a simple fault that seems to recur often on TTRs - it points to a jet blockage which is resolved by carburettor dismantling, cleaning, sorting and carefully reassembling.
Also the air filter may need attention and spark plug checking.
Please direct me to finding the thread on how to suss a lemon.
This is the first forum I have ever been on and am struggling to navigate any help would be appreciated.
I didn't ride the bike. The bike was idling and I rev'd it to see if the smoke would clear. In short the engine blew smoke for the entire time it was running (3 Min approx). The owner mentioned it has been garaged for the last 3 months with no use and the two issues mentioned above only started after this period of time. The owner does seem honest.