The Blog Oldracers posts - Grey Flash Diary August 2012

Grey Flash Diary August 2012

Vincent Grey Flash

My attempt at wheel building started with a problem, the holes in my Borani rim did not accept the normal 8G nipples so my choice was stainless spokes in either 8G butted down to 9G or plain 9G. Now after Russell Kemps little escapade on the Autobahn I do have some reservations about stainless spokes but as I am not intending to emulate Russell, (I don’t think many of us could!). Riding with camping gear on a rough road to Turkey, and back. Then a blast off to Germany two up, is not on my agenda so I think 9G should be OK. Also as the butting process causes discoloration the spokes have to be polished and since I want unpolished as that closer to the original cadmium finish, I ordered the straight 9G unpolished. Now a further delay has now occurred, as there is a wait for brass nipples
With the valves inserted I fitted the head in position with my customary play dough pressed inside, and then I turned the engine over TDC. It’s a good trick I have mentioned before but it allows me to check head clearances giving me reassurance that there is plenty of room when the valves are flying about. And also, when rolled in a ball and dropped in a measuring glass the dough gives me an accurate reading of clearance volume. In this case it was 55cc giving me a ratio of a tad over 10:1 (Hmm I shall have to bump this machine occasionally but it should be OK). If you try this method don’t forget to clean the spark plug thread (threads in my case) of the dough. You don’t want hard crusty bread deposits when you come to put the plugs in, or your threads will be toast (sorry!)
My cylinder man had a lot of facing to do on both ends to get the barrel square so before I finally fitted the head. I put the push rods in position and made sure they were the right lengths (there are 3 sizes available). Then on the final assembly, I tourqued the head nuts up to 30ft lbs. and left it overnight, and added the final 2lbs the next day.
Next step was to fit the UFM bracket with the best selection of steel nuts I could find (Remember its all coming apart again after fitting, for plating and finishing). I then fitted the UFM itself.
The refurbishment of the Girdralics draws nigh. And I have started to inspect the components, luckily I have collected enough original steel thrust cups etc and have sent them off for nickel plating, so that’s another place I wont have to resort to stainless steel. I have also noted that on many Grey Flashes, (The John Surtees bike for example), the FF11 handlebar clips had been rotated so that the handle bars pass under the upper link, and thread past the damper rod (no shroud). This entails the machining of the F1 head clip so that repositioning can occur. This mod does I suppose marginally reduce the frontal area but I don’t think it was a standard feature. I have never found that the standard handle bar position is obtrusive when racing, it would also disturb the standard position of the revcounter which utilises two longer FF72/1 studs for the handlebar clamps so I have decided not to proceed with that particular mod

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