The Blog Oldracers posts - Grey Flash Diary Jan 2013

Grey Flash Diary Jan 2013

Vincent Grey Flash

Although the fork blades are not with me yet, I did some work on the front end. I fitted the handle bar clamp studs with the RH side using the appropriate longer FT72/1 studs, and made up a bracket for the rev counter. Experience has shown, that there is a limited amount of time one can spare looking at the rev counter during racing, so I positioned the holes so that the 6000 rpm mark on the dial is at the 12 o-clock position. (That’s for visitors, I shall have my ‘dinner’ a bit later)
I have made up a V support plate for the front brake arm this well known common mod was enshrined in “Know thy beast”, and (accolade indeed); is obtainable as a kit from the VOC spares company, so I guess most racers fitted them. Of course there are those who do not subscribe to the whole big balance arm method, including some Scott owners (Yes some of those have balanced front brakes as well). Those heretics place two fixed anchor points on the forks and use a small pivot compensator on the handlebar brake lever itself, in a much simpler way. For myself I have a foot in both camps, At the moment the Comet racer has a bar compensator lever and an aluminium fixed fork bar as an anchor. This was done after many seasons when I removed the arm assembly to save weight, (unsprung & steering) and I must say I cannot detect any real difference. Of course the Flash is as much show as go, so a balance arm assembly it will have.
Just like the proverbial busses, on the same day, I received both the rear sprocket carrier and the thinned down Albion final drive sprocket. (I am using the thinner lighter 5/8 X ¼ rear chain). These deliveries give me an opportunity for some real progress. I have screwed the rear wheel together and made up the requisite spacers and accepted a donation of some thin felt from the good lady to cover the bearing on the sprocket carrier. Now I can fit it all together in the RFM, finalise the chain guard, the seat stay clearances, the final run of the back brake cable and fit the stand bobbins. I discovered an error in a previous diary entry where I quoted the RFM holes for the paddock stand bobbins as 9/16X20 tpi. That is indeed the correct size for the rear stand holes, but my RFM does not have those lugs anymore, since they have been cut off (Not by me Mister!). What I tapped out, were the two ¾ X 20 tpi holes below the main spindle these were originally intended (I believe) for a ‘sprung sidecar’. This is a more useful position anyway, since I have found with the Comet Racer when the bike is on the paddock stand, that bobbins in the rear stand holes have a tendency to make the removal of a back wheel and its spindle a difficult task. In my case good bobbins are essential as I swear by my Foxley starter on its wheels. Not for me rollers and a battery, try lugging that down to the starting paddock at Cadwell in an emergency.
I did some fettling of the primary chain case. Uppermost in my mind was that I had mentioned on the Forum the importance of running a ¼ whit plug tap down the threads of securing screw holes. So practising what I preach I gave a brief burst of WD40 up the holes and commenced to run my tap in. and soon was amazed at the amount of 1950’s red hermatite that came spiralling out, just as if I was drilling a hole in copper. When the new thin gearbox sprocket was fitted and the final alignment was checked, the Inner primary cover needed to be relieved a little on the inside. This consisted of simply removing the raised lip of the clutch shaft hole from the gearbox side with a hole saw in the existing depression. I then got the lathe spinning and carried out a general cleaning up of all the ½” and 7/16”shaft ends which proliferate behind the engine securing the gearbox and RFM. I found it a sensible mod to slightly counterbore the cranked link where the 7/16 through bolt exited and to raise a matching lip on the nut, so that when fitted in that restricted location, the lower through bolt could easily locate the nut and tighten. (The inner primary case was machined with a face to lock the nut)
When it came to the question of mudguards, I had some luck, I managed to obtain some old Birmabrites, old indeed they were, and covered in what I call white spot, obviously never to grace a concourse machine again but ideal for my needs. The front guard will need to be cut down, but must wait for the forks. The rear guard (some more good luck) was for a Comet and fitted easily into place. The end of that guard of course is square with holes for the hinge assembly, this will be fitted alternatively with either a small ‘nib’ bearing the club badge etc, when parading/racing or alternatively a second stay and some more guard plus number plate for road use.
I had the underside of the tank brazed up where I had tacked my carburettor recess tinware; it was a valiant task, which consumed a rod or two. On completion it certainly looked fully sealed and I tested it by filling it with some water, once satisfied I then administered my ‘SPLOSH’ sealant, together with my normal curses to the Ethanol fifth column of the EU. I have now sent the petrol tank off to the painters, at least I do not have to worry about gold lines since the Grey Flash tank (caveat: in most cases) was unadorned with such fripperies.

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