Grey Flash 2751

The history and restoration of a Vincent HRD Grey Flash

There has been a bit of a delay in progress as I have been busy with a time-consuming project and Bert has been engaged with other pursuits. The engine is in “last raced” condition and we want to leave it as-is so long as we can be sure that there are no issues that will (i) prevent its smooth operation and (ii) might lead to a catastrophic failure in the near future. Last rebuilt by Terry Prince, some three decades previously, it was only used sparingly by the Japanese owner prior to my acquiring it. Nevertheless, everything needs to be gone through methodically to ensure no disasters occur. The racing days of this machine must surely be over and it’s unlikely that from now on it’s going to be run for anything more than the odd parade/demonstration lap.

Timing the valves.

The valve timing was carefully checked using a degree disc. The values were as follows:

GF (Richardson P. 187)
Inlet opens BTDC – 55˚
Inlet closes ABDC – 68˚
Exhaust opens BBDC – 73˚
Exhaust closes ATDC – 50˚

Inlet opens BTDC – 59˚
Inlet closes ABDC – 84˚
Exhaust opens BBDC – 75˚
Exhaust closes ATDC – 48˚

These figures are close enough taking into account the specially re-profiled cams fitted.

Flushing the oilways via the oil pump quill.
Injecting clear honey into the big end…

No! Thinners was actually the solvent used to ascertain whether oil was able to circulate freely and lubricate the bottom end as intended. Once this was noted to be flowing unhindered then clean oil was introduced in a similar fashion.

The motor spins freely with no perceived issues. The oilways have been cleared and the valve timing checked. All is deemed satisfactory for the unit to be run in this “last raced” state.

One thought on “Checking Whether the Motor is Safe to Run

  1. Somer says:

    Ithink you’d gett beter reading of valve timing by measuring from valve springs vs. rockers.


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