Here's my two cents,
This is the readers digest version. I bought a 94 FE501 used from a guy who swore it didn't have that many hours on it blah blah blah. It was the first berg I bought. Long story short the guy sold me a clapped piece of s#@t. I spent $ 2000.00 on rebuilding the engine and carb. After that the bike ran like a scallded cat!!!! And was running great when I sold it to my good friend. He rode it for a season of racing and then had fourth gear go out at the beginning of the next season. This was when there was no HNA. The local dealer told him he couldn't get the parts he need b/c there wasn't a HNA. But b/c of the support from this site, I handed him the part two days after the local dealer told him they couldn't be found.l He fixed the bike up and traded it off for a quad for his wife a few months later.
Point being, like one of the previous posts said, he is my friend so I told him everything about the bike and he accepted the fact that the bike was used but well maintained. Buying a used dirt bike is a crap shoot, maybe the guy selling the bike is telling the TRUTH and maybe he isn't. I know that if I ever bought another used dirt bike, the first thing I would do would be to take it completely apart and go through everything, it's the only way to be sure that the bike will be reliable.
I know that there are companies out there who sell warranties. Just like extended warranties for cars, they can be had for dirt bikes. I don't know what the laws are like in Auz, but that could have something to do with why they have longer warranties than here in the states.
THE MAIN POINT HERE IS THAT IN MY EXPERIENCE WITH HUSABERG, ANY PART THAT HAS/HAD A KNOWN DEFECT WILL BE REPLACED BY HUSABERG. THEY HAVE REPLACED TWO SETS OF CASES ON MY 2001, AND THE IGNITION MODULE. I WONDER IF HONDA IS REPLACING THE HEADS, VALVES ETC... ON THE CR250X'S THAT KEEP WEARING OUT IN A VERY SHORT TIME???.