I've been bike mad for twenty odd years and always worked on my own bikes.
I've been buying cheaper, older bikes and giving them full rebuilds. Generally when I've got them to a high standard I get bored, sell them and find a new project.
I've bought five bikes through eBay in recent years. All of them have faults that would have shown up on a test ride and in my opinion people are trying to rip you off using the commit to buy situation of eBay.
My worst nightmare is the current Honda ST1100, sold to me with a brand new MoT which is obviously dodgy.
I have had to replace the swingarm, brake lines, bottom yoke, radiator and repair the crash damaged bodywork mounts
The fork bottom screws were also coming out and oil was dripping out.
The bike has mostly been in my workshop for the last 6 months.
On a positive note for Ebay, I've bought all the parts I've needed relatively cheaply and done a nice job of the bike. Had I bought it locally and gone round and looked first I'd have saved myself a lot of hassle.
The garage that MoT'd it was in Shrewsbury. I rang them to complain and they said "It must have been ok on the day or we would not have passed it."
I replied, "are you expecting me to believe that the seller refitted twenty year old brake hoses, a rusted swingarm and crashed the bike. Then coated it all in two years of rust and roadgrime after the MoT within two days of me collecting the bike??!"