A New Start For Your BSA!


Stephen Ronald McFarlane ( founder of SRM Engineering ) talks about his revolutionary new invention – the 1st Electric Starter for BSA A10, and A7,  You’ll be hard put to spot it when it’s installed and you’ll be glad to know that you will still be able to use the kick start – if you really want to! Just think of how easy it will be – and no more stressed out joints! Read on to find out why, how and all the details of this fantastic invention…..

The vision/motivation!

Last year at the Isle of Man BSA International Rally, (2008) Dave Brady (B.S.A.O.C. Chairman) and several others were talking about the need for an electric start for the BSA’s. Bad knees, hips and other bodily parts were starting to give way in the strain of kick starting their treasured bikes! One of my engineering friends had also been on to me about it for years but I’d always said the problem was that the chain case would need to be re-cast to give the necessary strength – making it too expensive to be viable – and it would be a hugely time consuming and difficult task to do! However after seeing a Vincent electric starter in the Isle of Man, it got me thinking about alternative ways of doing it….

My design objectives

Being a BSA enthusiast, I wanted to design a starter that didn’t spoil the look of the BSA. So my 1st design objective was to make it as discreet and inconspicuous as possible, yet still be able to use the kick-start. I also wanted the battery do at least 25-50 start ups, so a suitable battery was needed – and it had to be able to fit it into the existing battery compartment. I also wanted to make the kit to be a ‘bolt-on’ kit, with minimal modification, so that any competent mechanics could fit it themselves. Finally, I wanted to ensure minimal alteration to any existing components.

Figuring out how to do it…

In spring this year, ( That was in 2009 ) I started in earnest looking into working out how it could be feasible to drive the starter through the kick-start mechanism, using my BSA A10 Super Rocket (with 9:1 compression pistons) as the project bike. After many hours in my garage looking at cogs, gears and sprockets that I thought might be suitable, I was unable to work our how to drive the engine this way without losing the use of the kick start. I didn’t want to lose this, as I believed owners would still want the option of kick starting. Also, I would have had to cut away some of the mudguard on certain models.

So I looked at driving the starter through the chain case, without putting any load or strain on the chain case. Then after many more hours of looking at my chain cases, gear box and engine plates, I devised a method which would not put any strain on the chain case and then I had to work out a suitable gearing arrangement – then convert all my ideas into metal! Through many more painstaking hours of machining, cutting, filing, grinding, boring, drilling and the like, I finally turned my ideas into working metal pieces!

Eureka – it works!

The 1st electrically powered A10 start up happened at around 1am on Saturday morning, 30th May! It worked, with both inner and outer chain cases completely removed to prove it didn’t need the chain case! I was absolutely delighted! It was then another week of still many more hours of hard work to do the last bit of finalising, fettling and machining before it was finally complete. Then on the afternoon of the following Saturday 6th June surrounded by family, with eager anticipation and the video recorder running, I pressed the starter button and it started! Everyone cheered and I was ecstatic that all my painstaking hours of hard work had paid off.

Testing, testing…

I did 200 start ups (with the charging system disconnected), counted by my family and many of which were video recorded. After 250 starts, the whole starter mechanism was stripped down and examined for wear. The prototype gears were deliberately not hardened for the test (all production gear sets will be hardened), as I wanted to assess any early signs of wear and to accelerate any aging of the gears, in order to assess the long term life of the gears. I really thought the gears might wear at a higher rate, but they showed little sign of appreciable wear.

I have exceeded my design objectives, because after 200 start ups, the battery was down only half a volt! If your battery is fully charged, you should achieve 250-300 starts. So, if your charging system fails you can still be confident that you can start your bike! To date I have done in excess of 4,500 starts and over 8,000 miles in testing. [now 2016]

As this is a new invention, I wanted to protect it, so it was time to get in touch with the Patent Attorney, who prepared and filed the patent;  Patent Pending No: 0910152.8,  1009795.4,  GB1009795.4  and design rights apply.  

Patent Granted: 22nd October 2014, GB2471022

Launch Day! Wicksteed Park 2009 BSA Open Day & National Rally, 14th June

I was ready to launch my new Starter! I arrived late on Saturday, so on Sunday morning I decided to show Polly Palmer the starter working on my bike. I then intended to have breakfast, but after only a few minutes, the sound of the electric starter attracted a group of around 10-15 people… For the next 3 hours or so, I demonstrated the starter and said to people; ‘Do you like the special feature on my bike?’ I asked them to try to find out where it was – I was pleased that most people could not detect it, as this was one of my design aims. After showing them where it was and how it worked, they were saying ‘that’s brilliant’ or ‘that’s fantastic’. Even some of the ladies started up my A10!

What you need to do to your bike

The only modifications needed to your bike are; to drill 1 hole in the primary chain case, bend over the right and left tabs on the battery compartment (to accommodate the slightly wider battery; the original clamps are still used), make some wiring mods, some alteration to the engine sprocket ( fitting a gear to it )  the rest is a bolt on job. You will also need a 12v charging system of preferably positive earth.  I can do a - earth starter but this is slightly more expencive. 

For the initial orders, I will need to fit the starter at my workshop to check any discrepancies or variations between models that might need to be addressed. There will be a fitting charge for this, but hopefully it should only take a day to do. 

I have found that even though I am able to kick-start my bike I am using it more as it is such a pleasure having an electric start and I can honestly say that I love my A10 even more now! I have a Hinckley Thunderbird, so I have been spoilt having an electric starter.