I remember those bench plug cleaning machines. I used to wire brush my plugs a lot when racing, so I got a clean plug reading next time they were out.
When I did the Manx GP Newcomers race, I decided to fit a set of proper race plugs to my CBR600, as an insurance policy against the amount of time you are at full bannanas on the TT course. To my horror, they were £66 each - in 1997!
Plugs and good fuel are always cheaper than pistons however.
When I was at Manchester University there was a lad who lived nearby who an air cooled Yamaha RD350 which was forever oiling plugs in the traffic. He wore an old long dark brown leather coat, with big, stretched side pockets full of spark plugs.
