Author Archives: johnhealy

Triumph Valve Dimensions


Converting Miller Generator to Lucas Wiring

To use a modern voltage regulator the Miller generator must be rewired so it works like a Lucas generator.Click on Link below to down load a printable PDF millerconversion 

Rod Coates was pushing for a factory dirt track racer before the T120RT

Rod Coates was pushing for a factory built 500 racer before the AMA allowed 750cc engines to run professional dirt track. The T120RT was a skunk works operation that eventually cost him his job. Click on the link below to view letter by Rod Coates to Tricor general manager, Earl Miller. Rod Coates factory dirt […]

Triumph T120RT

Click on link to PDF below for more information on the T120RT: Triumph T120RT – web

Valve Seat Information

Click on link below to download a PDF file containing installing valve seat information: 650-750head

Amal – A comprehensive look

AMAL Concentric Carburetors (updated to include Premiers) I gratefully accept comments, and criticism. They can be sent to johntioc at THE BASICS: Get comfortable, this will take time to read: It’s the needle jet stoopid: (coined by Don Hutchinson who co-hosted many of my Tech Sessions.) If there is one thing you come away […]

Push Rod Tubes

Triumph 650 and 750 Twin Push Rod Tube Crush From the first day I read the phrase in an book by Mike Hailwood, “Dropping a piston circlip into the crankcase is a confounded nuisance” I knew exactly what it meant and how it applied to me. Let me explain: There are just some things in […]

Oil Leak – Crankcase not even

Checking crankcase mouth for step. In the technical world we live in today imperfections are rare. In the day when these bikes were made they were common place. One that catches many mechanics out is a step between the two case halves. Sometime in the 1970’s someone at the factory decided that could speed things […]

Triumph Crankshaft

Changing Triumph 650 4-Speed to a 5-Speed

Update To A 5-Speed Gearbox There have been many iterations of the Triumph 5-Speed transmission. Not all 5-Speeds gear sets are the same. The early gear sets first offered in the 1971 model year turned out to be problematic. If used hard they would break. This wasn’t discovered during testing, but only after the bikes […]