Tim Thearle: a brighter spark
My father (and possibly your father) used to say, “Ninety per cent of carburettor troubles are in the magneto”. It is an axiom that has stuck with me all my life.
It was while on the 1978 International Vintage & Veteran Car and Motorcycle Rally that Tim Thearle first began to consider the vagaries of the mysterious device that (hopefully) supplies the spark to fire the mixture in an internal engine. “We were stopped by the side of the road east of Armidale when the magneto was failing on my father’s 1930 Rudge...the first of several hints that the magneto must be rebuilt correctly! Like most folk, magnetos were little understood by me for many years....you know, clean and set the points and replace the spark plug occasionally and the thing should work!” “By the early 2000s, and after numerous rebuilds of British bikes, always relying on the dwindling number of magneto specialists about, a change of working life experience in 2006 prompted me to pursue what had been a hobby until then with motor bikes; to open my own business and work for myself. Initially fulltime motorcycle work developed into repairing/supplying rebuilt Smiths speedo drive gearboxes, tacho drive gearboxes and drive cables, as this was when Dennis Quinlan retired and I bought that part of his business. Soon after I decided that the magneto repair options were very limited, so I met with Ivan Brown and he was good enough to train me in his workshop, and allow me to utilise his equipment, until I was satisfied that I could pursue this trade on my own. Importantly Ivan was a mentor for several years before he died, and was always happy to assist with specific queries.” TT Enterprises thus became the go-to spot for magneto repairs, and has remained so ever since; with a workshop specifically fitted out for the task. The necessary equipment was purchased from within Australia and from the UK, with some also coming from magneto specialist Bob Gardner in Melbourne as he wound down his business. “I consider some coatings and insulation have improved since mags were everyday fitment,” says Tim, “which we use to our advantage, although I still favour the old style golden lacquer to finish and bake the coils with. A good coil is certainly critical to a healthy spark, but there are many other factors to get the right results, and since the instruments are getting pretty old every component, such as the Bakelite parts and individual insulators in the contact breakers, as well as the magnetism, needs consideration in the rebuilding process. Over the years folks have often got by with a ‘quick fix’, but now complete rebuilds are essential.” “Specialised magneto and dynamo work now amounts to about 90% of my time, with customers across Australia and also in the U.S., Hong Kong and New Zealand, where I did the magneto for Dave Kenah’s very successful Manx Norton. Apart from end users, two well-established old bike dealers in Victoria send their mags and dynamos to me for rebuilding. It’s interesting to observe how customers change their attitude towards magnetos once they’re using a reliable rebuilt unit – old bikes don’t have to be hard to start! I receive magnetos that have provided good service for many years and only now need major attention. A well set up mag will happily provide ignition for decades to come. As a device for ignition they are extremely reliable, even under race conditions; why complicate a bike that was produced with a magneto with electronic ignition?” Tim has had a 46-year association with Velocettes, is the proud owner of one of the original Sportsman models sold through Burling and Simmons shortly before Velocette folded, and is currently the Velocette Owners Club Inc., secretary. After many years in Orange, NSW, Tim and his business are now located at Alstonville on the state’s north coast. So if the spark has gone out of your motorcycling romance, give him a call on 0417 892766 or email tim.thearle@bigpond.com