9. Front Forks
|What I am trying to say is that when I decided
to build a Vincent for racing, it was as much because I loved the idea of
building a Vincent as it was because I thought it would be unbeatable in
Sure, I was hoping that the power of a big Vincent might give me a better chance of being competitive, (an area that I had been struggling with my overstressed ES2 based Norton), but I was not expecting it to be up to much in the handling stakes.
I admit that even now I have still not raced a Vincent in anger, so I can only speculate, but I am not expecting miracles and it might be this aspect of the bike that determines how I use it once it is finished. When I first started building the Vincent, Mickey Carter was racing a very potent Vincent in the unlimited pre-58 class. If you looked closely at this bike (see photo) you could see that some very novel ideas had been incorporated into the bike to improve handling (I believe well known Vincent exponent John Renwick had helped with this development). The main feature is that the centrally mounted damper had been replaced by a modern spring/damper unit, that looked fully adjustable. This alleviated the need for the spring boxes behind the blades and these had been removed. It had been done very neatly and therefore was quite inconspicuous.
Also visible, (although not immediately obvious) was a rod seemingly connecting the lower fork link to the petrol tank! On closer inspection all became obvious, a false fibreglass petrol tank had been fitted and through this protruded a steering damper. The 'real' alloy petrol tank sat underneath, on the right hand side of the UFM, which also left room for a battery to be fitted on the left side. At the time I was quite taken by these mod's, fully intending to try something similar myself (in fact I did buy a false tank from John myself), but have conceded that I am now unlikely to race the bike seriously and have settled on a more traditional setup.
Refurbishing the Forks
|I bought new spindles and replaced all nuts bolts and fittings with stainless items from Maughan and Sons. At this point it is probably worth pointing out that the Maughan family, apart from being fine engineers, produce the highest quality stainless nuts and bolts I have ever seen. Each bolt is a work of art with every bolt face burnished to a beautiful bright satin finish. In my opinion, it's this sort of finish that makes the difference between the average restoration and a real quality restoration. I normally end up having to make most of my own fastenings when restoring a bike, but in the case of the Vincent I allowed myself the luxury of buying 90% of them from Maughans.|
|I passed the Lower Fork Link (FF3) and new sintered bronze bearings to Don Alexander so he could ream them after fitting. In the end though, Don fitted his own one piece bearings which I think are a better solution. He then line reamed them both together to ensure complete trueness. I fitted the other new phosphor bronze bearings in the remaining links, and also took the opportunity to fit grease nipples (I remembered back to watching my father fitting them to his Comet when I was a boy).|
One of the well known features of Vincent's racing 500cc bike, the Grey Flash, was that the fork blades were milled down their inner faces, which I assume was to reduce unsprung weight. Bearing in mind the points I made earlier about handling, I thought this was a mod well worth making so asked Don if he could also make this modification for me. I don't believe it was actually made on real Vincent Black Lightnings and I assume that this was because a lot of Black Lightnings were used for sidecar racing, presumably the risk of weakening the blades was too great. I had no intention of attaching a sidecar so did not consider this a problem (my father also has a spare set of blades should I later change my mind).
For the moment I have fitted a Koni damper which I aquired from Ted Davis. I am told these can be overly firm until bedded in though, so will probably fit it to the rear suspension for the first 1000 miles or so. My father has some old original Vincent dampers in his spares collection and I am quite tempted to have one of these refurbished with modern seals, I will have to see if I can think of something he wants to tempt him!
The outer springs fitted are the standard solo springs, but I have also fitted the smaller inner springs, as fitted to twins only. Originally I considered special spring/damper units (as per John Surtees bike) but have now decided against that idea on the grounds of originality.
Finally, I considered what type of finish to apply to the forks. I was tempted to have them plastic coated, which gives a very durable finish but is not always free from blemishes.
As I was looking for a concours finish for this bike, I decided to use an acrylic 2-pack paint as used in the automative trade. I have used this paint before and know that if prepared correctly it can give the most beautiful finish, but is also very durable and strong.
|The secret to this durability is
to ensure the base metal is absolutely spotless, then to apply a thin coat
of Etch Primer, followed very quickly by a 2-pack primer. Once these first
2 coats are applied you can then continue to add coats and rub down before
applying the final topcoat. As I am sure most people are aware, 2 pack paint
is extremely dangerous to apply without proper breathing equipment. As the
paint and hardener chemically react they rubberise, if you are breathing
the paint in to your lungs the paint will rubberise on your lungs and damage
them permantly. I used to carry out the painting in my largest shed, with
a North mask running an air pipe out through the shed wall, which worked
The finished results are extremely hard, and although I say it myself, do not look too bad at all. The down side to doing it yourself is that it is very time consuming and demands a great deal of effort be put into the preperation, especially if you do not have a dedicated paint shop. I have to say though, doing it yourself does give tremendous satisfaction and at least you know how good the preperation has been.
|Final Assembly (well not quite!)
Assembly so far has proved quite straightfoward, apart from the fiddly process of building up the correct shims to the eccentrics and lower link (see photographs). There is probably a technique to fitting these shims without damaging them, but I have not found it yet. Once this was achieved, however, everything else was straightfoward.
The eagle eyed out there might also spot that the lower damper eye bolts (FF57) are too long. Not sure why I bought these longer ones, but I think they will have to be replaced by the correct shorter ones before I put the bike on the road. I'm not sure if it makes any difference but read somewhere once that it is quite important.