Grey Flash 2751

The history and restoration of a Vincent HRD Grey Flash

Much re-designing to the 500cc cycle parts was required by Vincent HRD to accommodate the Albion racing gearbox. The standard road-going Comet and Meteor utilises a Burman gearbox and everything was designed to accept this proprietary unit. Fitting the Albion gearbox required special brackets, unique to the Grey Flash, and major surgery to other parts.

The plate in question.

When acquired, I was able to see that a spacer was inserted between the inner primary chaincase ands the Albion. Its overall appearance hinted that it might not be original to the machine.

Indeed, once the bike had been broken down we could see that something didn’t look quite right… This fabricated adaptor plate had served its purpose well but was obviously not original. The inner primary chaincase certainly was original; it was stamped with the correct “42” assembly number.

I needed to get to the bottom of this and so contacted the Grey Flash “Oracle”. David Dunfey elucidated: our inner primary chaincase was indeed correct and machined as it should be; the cast-in boss, where the bottom-most stud to secure the Burman ‘box exists, has been machined off and a lot of material relieved. The reason for this is so that a much more substantial adaptor plate could be utilised.

A standard inner primary chaincase.

David obliged with pics and a clear description of what was needed. A new plate would need to be fabricated…

This is what was required. Image courtesy of David Dunfey.

This would be no small task as the plate features a crank.

Image courtesy of David Dunfey.

Bert set to work. Once finished, he stated that this would not be a job he’d like to repeat…

Much effing ‘n’ blinding was needed to get this dogleg just right!!
Our plate doesn’t feature a captive nut – I’ll be able to elucidate as to why once I’ve spoken with Bert.
In situ.

The fabrication of this part has been a difficult job. It couldn’t have been done without Bert’s skills and David’s generous advise and expertise. The excellent result means that the machine is now a little more original than it was when I acquired it and has been returned to factory configuration. Top job!

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