all I can say is be frightened, be very very frightened!
seriously I have never ridden one of these 'widowmakers' either but all the stories I've heard of the TM400 in standard trim made my bum pucker
I wish I could remember his name but I met a guy at the Maleny swap meet a few weeks back. Big bloke and no flyshite like me. He had a few questions about what ignitions/weights/flywheels and such he could fit to his TM400 he'd recently imported from the US. After talking for a while I got curious and asked why the bad limp. Story goes, on his very first ride he took off, slipped into second then third then gave it just a little rollon and the whole world changed. He said it simply came into the band and accelerated that hard it caught him totally unawares spitting him off and breaking his leg badly. This was in a straight line!!
he said it was out of the blue and it was not controlable. I tend to believe these stories now as I have heard so many from so many reliable sources. I'm not so sure it would be a good idea to ride this model without making the TS400/185 flywheel/stator swap
not trying to pump up the TM400 but shit, I'd be more than a little wary riding a stock one!