Grey Flash 2751

The history and restoration of a Vincent HRD Grey Flash

The original FT3 that we obtained from Franc and Greg, down in Australia, has been drilled.

The drill pattern is accurately recorded on a Works drawing which we had.

David Dunfey kindly supplied additional data which enabled us to drill with confidence. He also furnished us with photos of the original FT3 from his GF.

The finished item.

Once the lockdown has lifted and businesses are up ‘n’ running again, this will be sent off to the platers for the application of the correct dull chrome finish.

Dyl boy has carefully inspected the drilled FT3 and given it two claws up. 👍🏻

A moment of assembly this early in the process of restoration is a cause for some elation. The rear rim was exchanged for the correct 20″ item early on in the project and now the refurbished drums have been bolted to the hubs and offered up to the forks and RFM.

The rear drum.
10 bolts now, as per original.
The front hub – a very pleasing result.

The above photo features lots of incorrect parts that will be attended to later. The Elektron brake plates are still too shiny and will take a few years to dull down. We have found an American product on the market called Eagle One Etching Mag Wheel Cleaner – this should produce a pleasing dark matte finish but we’re currently unable to find any for sale in the UK.

We have discovered that the front hub features a metric bearing setup. Due to a shortage of materials during the Korean War, metric bearings with an o/d of 47mm were fitted in place of the standard Vincent item. So this item is not the original hub as 2751 was completed and shipped prior to the onset of the Korean War.

The hollow front axle complete with bearings/spacers and shims.

What to do? Replacing the hub with a new pattern item and fitting standard bearings was one option. Another was finding a period hub and hollow axle and fitting that. The former of these options is the least desirable as we would be replacing period items with new ones. The latter option seemed more in keeping with the level of authenticity we are are trying to achieve but we have decided to go with what we already have. The reason for this is that (i) it’s a genuine period hub (albeit of a little bit later vintage than what would have been fitted to the bike when new) and (ii) was used during the bike’s racing career. In addition, it features a hollow axle machined out of lightweight alloy. These were sometimes fitted to Vincents though we’re not sure whether this one is original or made at a later date. Anyway, it seems entirely appropriate to preserve this lightweight component on a racing machine.

This hub would have originally been fitted to a road-going Vincent with a speedometer as these drive gear ring retaining punch marks attest.

Recent inactivity is due to the fact that we have been awaiting and sourcing parts.

A large order of parts arrived from the VOCS.

Clutch plates for the modified Norton clutch also arrived.

As has been previously explained, the trick Norton clutch will be retained. This component is imbued with the bike’s racing history and to sideline it in favour of an original Albion unit seems almost criminal. Why delete parts of the bike that were used in-period just because they are unoriginal? It would not be particularly hard to source the correct component and return the bike to the spec’ that it left The Works with. However, we’ve decided that choice non-original parts, that were used in anger and are part of the machine’s DNA, will be retained and will be a fascinating reminder of the people that raced the bike and its racing pedigree. The character of 2751 needs to be preserved to attest to its very full and hard working life.

Head bracket as acquired.

As mentioned in this blog waay back (run a search for ‘Frames and Brackets’), It was discovered that the special drilled cylinder head bracket was found to be of the wrong pattern as the drilling appeared crude and didn’t match the drilling pattern of drawings held on file. This was a bit of a blow and the only recourse we had was to drill a bracket to original spec’. Finding an original bracket seemed a tall order and modern reproduction items differed in several ways and were completely unacceptable for this project.

As so often has been the case, Franc Trento came to the rescue! He mentioned we were looking for one to ace Vincent mechanic Greg Brillus and Greg was able to supply.

Original FT3 cylinder head bracket.
This will put to good use.

This is currently winging its way to the UK. It will be correctly drilled and dull chromium plated as per the original. Thanks Franc and Greg, you beauts!

2751 employs a modified standard nut that’s been turned down and drilled for lock-wiring.

This has probably seen many races…

The problem that we have here is that threads of this lock nut have lost their crisp profile whilst the female part of the equation is well worn. When nipped-up one is conscious that one day it’s going to go one nip over the line necessitating surgery to the cylinder head! A new nut has been ordered to see whether it will take up some of the slack. It will be altered accordingly.

The profile of the exhaust pipe as acquired.
The original pipe.
Another good profile shot.

We have yet to make a decision about whether to retain the current exhaust pipe or fabricate once closer to original pattern.

This is so cool!

Peter fabricated this pipe that crossed over to the drive side for use with tight right-handers at Bathurst (if I remember correctly). I did enquire as to whether it still existed but it had long since gone. I think that if I had it in my possession I’d seriously consider fitting it.

…Or lack thereof. We removed the oil filter element chamber cap.

No element or associated parts, just a void.

The bike would have left The Works fitted with an element and we will reinstate one. At some point, possibly during Peter Johnson’s tenure, this assembly was omitted as it restricted flow and anyway, the oil would have been changed every meeting or so obviating any need for such a device. A little less weight too for a bike that was becoming more and more competitive… “Adding lightness” is the one tuning modification that seems to only have benefits for increase performance and handling on every level.

The incorrect BTH magneto is still fitted and just visible here.

Peter got back to me straight after I posted the above:

“No oil filter, no grease in wheel bearings, or seals… Oiled each meeting; less friction. Although weight is critical, my friend Ralf Engelhardt (BMW 500 sidecar champ with Klaus Enders), reminded me that 2kg equals 1hp whilst the bane of small engines is friction… Formula juniors (1100cc, 125hp and just enough torque to pull the skin off a cold custard) only used 2 piston rings for that reason.

I would eat salads for 3 days before a meeting, and fill up on pasta, etc on Sunday nights when the racing was over – and I was only 63kg then.

The fast engine (Comet cases) that Terry Prince built for me would turn over under valve spring pressure – beautiful.

And yes, the oil was changed each meeting, and the exposed primary and rear chain cleaned and re-oiled.”

Thanks for that Peter – fascinating! And it shows just how seriously you took your hobby and gives an insight into the drive and passion exuded.

Grey Flash models employed 10-bolt rear hubs as per the Black Lightning and road-going Black Shadow. The flanges and drums are bolted to the hubs using special high tensile bolts and locknuts sans washers.

Simmonds locknuts.

These early locknuts are of the correct pattern and feature fibre inserts. Although we have some in 5/16″BSF we do not have 30, which is the amount we need to complete the job. New bolts and Nyloc locknuts will be employed instead, and, at £4.93 per bolt and £3.32 per nut (plus 20% VAT) this considerable expense will surely be quite a bit cheaper than making a set replete with fibre rather than Nylon inserts. Fitting new fasteners does not give us any pleasure…

The brake drums fitted to the bike had been incorrectly painted grey.

Five-hole drums from the front.

Stripping off the grey paint was a laborious process; between the fins being particularly time consuming.

Ready for painting.

The drums are probably the first parts of this restoration that are finished and ready to fit. Once dry, they will be stored away until re-assembly.