Welcome to the forum. Firstly I want to say, you are never too old to start Parade Riding and Sprinting, perhaps even Classic racing, I will be 66yrs of age later this month and only recently took up Parade Riding..
I want to explain something at this early stage, Parade Riding can be done using your ordinary DVLA driving licence motorcycle entitlement however when you attain the age of 70 years you now have to apply for a licence to even Parade Ride a motorcycle and this incurs the cost of applying for the licence and also probably getting the application form signed by an Optician and a Doctor. The same applies of course whatever your age if you want to go Racing as you would need to apply for a Competition Licence and also go on a one day course for someone to assess your ability on track..
That said you can of course Parade ride over the age of 70 years without the need for a Parade Licence at such events as the Festival of 1000 bikes , although you are still riding on a race circuit they are not governed by A.C.U regulations.
I am looking at only another 3 years Parade Riding before I need to apply for a Parade Licence. it remains to be seen how I am physically as to whether I retire from Parade riding with Classing Racing Motorcycle Club and British Historic Racing and just go out at the Festival of 1000 bikes event, not exactly the same as gong out riding every month with the other clubs during the racing season. I mention it because you will be faced with the same decision in a few years time so do you want to spend a lot of money on creating a full blown race machine at this stage.
My first question to you would be along the lines, What do you want to do with your Arrow? Parade ride, Sprint it or Race it? you would need to decide so that you can build an appropriate machine, you can build an all out twin carb Racer that you could then also use for Parade Riding and Sprinting but even a race machine on which to be remotely competitive in Classic racing these days would cost thousands to build even if you can do much of the work yourself, are you prepared to spend lots of money on such a project when for a few hundred pounds you could be build a machine to Parade ride and use in Sprinting.
Let me mention the Sports Arrow that I've been Parade Riding for the last few years, a machine that has given total reliable service resulting in enjoyment and satisfaction just Parade Riding (and the occasional Demonstration Sprint). the Arrow itself was built by Ariel to take part in long distance endurance races at events at Thruxton and Silverstone in the early 1960's when the races lasted up to 9 hours in duration, the riding stints shared by two riders. it finished 2nd in all of its entries in 61 and 62 including a 2nd in class at the 24 hour Barcelona race in Spain in 61, (beaten by a 250 Ducati) can you imagine racing your Arrow for those periods of time today when a Classic Race these days lasts about 15 minutes on average.
The Arrow at first glance looks pretty standard in appearance although it has a rather basic rear set arrangement, so basic on the offside that the gearchange lever has simply been shortened and fitted in reverse, but it works o.k. there's a little bit more to the rear brake lever/cable arrangement still rather basic but works efficiently, this set up allows the fitting of the rear chaincases usually discarded to save weight.
The crankshaft comprises standard Ariel webs that have no padding of the flywheels and no plugs in the balance holes, there is no need to do this, it was accepted practice back in the 60's but the idea of thinking these days is to have as much room in the crankcase as is possible to get a higher volume of fuel mix in rather than padding that restricts the amount. o.k. I accept there are reasons for plugging and padding on some engines but not necessary for Parade Riding.
The con rods are Alpha con rods that appear to be sturdier units but they are far from being streamlined like Ariels Oval con rods but they've been in the engine now for 5 years and I feel no need to strip the engine down just to have a look at them. Ariel con rods would be o.k for Parade riding.
Pistons are Suzuki X7's of a a decent make, I would recommend using X7 pistons for Parade riding but I wouldn't recommend you use Ariel/Hepolite pistons because of the likely chances of them seizing, the Suxuki X7's made of a better quality alloy have a better/reduced expansion rate as they warm up and get hot. (other Japanese pistons can be used such as CR125 pistons) but X7's are perfectly up to the job for Parade riding but because they are shorter in length above the gudgeon pin this means they dont quite come up to the top of the barrel so its best to have the top face of the barrels skimmed to restore compression ratio.
For Parade riding you can use Iron Barrels as they are on my Sports Arrow but you would need to have them ported, that porting work has to be done to a certain degree to match whatever exhaust system you are fitting, I've got standard exhaust pipes and silencers on my Arrow, there is no point in having a pair of barrels ported to the hilt and using standard exhausts and silencers as it would't work efficiently, it would need a set of expansion chambers to be manufactured to the right shape, if you cannot do this yourself then its another cost to add to the project.
For Parade riding you can use the standard gearbox although you might want to experiment with a different sized rear sprocket, on my Arrow that is fitted with a four speed close ratio gearbox during its early period of Parade riding it just didnt want to run flat out in 4th gear until I fitted the larger 49T rear sprocket from the Arrow 200.
As for close ratio gearboxes it might be a little hard to find one these days, they are out there if you shop around and advertise for one but all is not lost because for a little more than what you might pay for an old close ratio box you can have a set made by Ellis Moore of Moore Performance Engineering, Manchester who has just made to sets for me to use on other projects.
As for the carburettor, you could use the Sports Arrow carb a 376/277 unit suitably jetted, on my Arrow as the inlet had been enlarged to take a larger carb I use the larger 389 carb of which there are loads in circulation especially on ebay so easy to source. Again as a matter of interest the main jet size is a 570 quite a difference when you consider 230 is standard size main jet for the sports arrow.
I've stuck to using the Amal monobloc carb because thats what I'm used to although you could fit a Mikuni carb these days.
Important mod to do if using the monobloc carb, you need to improve the fuel flow into the carb to ensure adequate flow when running long periods at speed, the standard set up isnt really up to the job so you run the risk of the carb drying up and the engine seizing so order a new Needle jet machined to take the larger Alcohol float needle. (I get mine from Surrey Cycles).
Now this might surprise you but the electrics are all standard 6v points and coil ignition and it works perfectly, no need to splash out on a expensive electronic ignition unit, the only change I've made, and you can do this an road bikes also is to fit a points back plate as used on Triumphs and BSA's in the 60's (6ca) that allows much finer adjustments on each cylinder to set the timing as the plate carries only the points, the condensers are relocated onto a bracket inside the dummy tank. To get the best out of points I do check them after every couple of Parade runs as they can drift off a bit, I also run a flattened cotton bud across the points themselves to clean them of oil mist that inevitably circulates and gets onto them.
I'm not against electronic ignition units, I have Pazon fitted to two of my Arrows but trying to keep this particular Arrow close to originality as it was when raced in the 60's I'm happy to stick with the points system and checking the timing frequently.
The next stage would be to remove all the excess weight of dummy tank, mudguards, tail section, add a fibreglass tank and seat unit, 18" inch alloy wheels, Ace bars to create something that looks more like a racer, you could stay with a single carb engine but fitted with expansion chambers will still be useable for Parade riding and Sprinting.
A little more expense to build perhaps but not excessive.
Or go and build an all out racer with twin carb engine, fully ported crankcase, Alloy barrels with boost port at rear, Kawasaki con rods, Prox Cr125 pistons, matching expansion chamber exhaust system specially made, improved Maxton front suspension units, strengthened rear swinging arm unit, better quality rear shocks, an alternative usually a Japanese front hub with twin leading shoe brake, you might want to change the rear wheel hub also although you might be able to retain the Ariel hub fitted with suitable race linings, race tyres, electronic ignition, Scitsu rev counter, 6 speed Nova gearbox a must to be competitive (if you can find one as they are no longer in production, they cost when new around £1800 plus vat ouch) so even used Nova boxes when they come up for sale are not cheap topped off with a race fairing.....
As mentioned, depends what you want to do with your Arrow and how much you are prepared to spend on building it.
I do not carry out any porting work on the crankcase and barrels, I leave this to the expert, Ron Phillips of Fahron Engineering, Linby Notts who advertises in Classic Racer magazine.
Good luck, I would love to have your company out on track Parade riding our Arrows together so go for it.
Can you get it ready to ride with us at the Festival of 1000 bikes event in July at Mallory Park when every year a small group of Leader/Arrow enthusiasts meet up to ride on track in the same track sessions, if so. entry forms are now available through the Vintage Club website, you don't have to be a member to parade ride at this event.
Roger James. (Jess)