Spark Plug Question

[BillN]

I have an R60/5 - they are renown for a slight pinking - although it has an electronic ignition fitted, it still pinks slightly under load

Is it possible to reduce this by fitting plugs with a different heat range? - hotter or cooler

 

[John Roberts]

Dad had one and it did pink a bit. That had aluminium shims under the cylinder bases which were meant to reduce the compression ratio. For all I know they might well have reduced the pinking but they weren't a complete cure. He had a couple of spares, if I can find them would you be interested? (Free of charge, natch.)