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Grey Flash Diary Jan 2012

surtees vincent 1951

The Comet racer has priority in the workshop, so after a quick struggle with a slide hammer and a poor heat source, I farmed out my Grey Flash oil pump sleeve and new cam spindle to Roger Forsyth who is just down the road from me. (Just as well I did, the extractor hole in the rear of the pump housing had been made with a taper tap!)
I went through all my barrels and found one that would suit “The last batch” of new +20 piston from the Spares Company. I think 9:1 is about the best compromise for road /parade use on today’s eco rubbish.
I am reducing the Comet racer back to 500, this entails a large top hat bush to fit in the widened crankcase mouth with the top hat ‘rim’ under the barrel. and clever Trevor has obliged. This of course necessitated a very high compression piston to allow for the ‘rim’. Nothing over 9:1 exists anymore so I had intended to go back to an old 60’s trick of fitting a B50 piston with (because of the smaller pin size relative to Vincent one) a floating small end bush. However I then found/remembered that the Carillo rod runs direct on the Vincent gudgeon pin without a bush and its small end is larger, So I decided that the B50 bush would perhaps be too thin. (I was also supprised by the price of aluminium bronze). Luckily some people read the classifieds in the forum; (A much under used facility). And Roger Barton came to my rescue with a parts swap for some lightly used 11:1 specialoids. These together with a light cut on the muff faces gave me the possibility of sneaking near the 10:1 target for the racer.
I also have discovered why Mr D Dunfey needs a hole in his petrol tank. Now the Comet is going back to 500 I have decided to try again with the big Gardener Carb that Mr Mettram Kindly lent me in 2009. But, by the time I had a decent length and found a suitable inlet arrangement, the bellmouth neatly fitted the riders left knee! And turning through 180 degrees soon found the roof of the tank in close proximity. So another job was born: - get a tank with another hole in it.
I made a dummy UFM out of a piece of wood with an old twist grip and rubber for the oil tank neck, but after getting so far, it was obvious that a better idea of just where the carb would protude was required by the fabricator, “I need the bike” came the call.
This was a problem, the Comet was in bits, and my comet UFM was ‘in work’, so I pinched the Grey flash UFM added a cylinder head, carb and bracket and popped it in the car boot. I curse (as many do) that with a Vincent you have to build the engine before you can build the bike, but sometimes it can work the other way.
Meanwhile back on the Grey Flash front Bob Newby received an Albion main shaft and could start work on the clutch and belt drive but his work soon came to a juddering halt since without a crankcase half I could not mock up the gearbox arrangement in order to give him a range of mainshaft to clutch centre dimensions.
It does seem that at this point in the year when all the parts for all the bikes are in all corners of the country, that it’s enough to make you start polishing (not quite.)

  • Posted on Mar 8th 2012
  • By Tim
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