Hi to you all.
By way of introduction, I am the proud owner of an original BSA 1960 Spitfire Scrambler. I understand the frame and engine numbers are correct and as it left the factory. I purchased it last year and it has, during the course of its 62-year life, been converted to a road going bike and now bears little resemblance to its original identity. I am in the process of doing a complete nut and bolt restoration and will return it back to stock specification (but maybe with a few of my own preferences into the mix) and have opened up this topic/thread to show you all the progress along the way, which I hope you will enjoy and find interesting, but also in the hope that I may elicit information from you that may help me with some of the more technical issues. So please do contribute.
I'm hoping that I have managed to attach an image(s) of the bike that shows the state when I first bought it. You may notice that it has been fitted with awful ape hangers, the front and rear mudguards (fenders) are incorrect. It has been fitted with road style exhaust pipes, the tank is not as original, and a previous owner has welded passenger foot pegs to the swinging arm - of all places! There are many other nonstock items, but I'm going to set about striping it all down and start afresh!
Not sure if the image(s) will attach in the correct place but here goes.
OK, those images seem to have attached alright.
So I set about stripping everything off the bike and making an assessment of what I had. Front and rear wheels were buckled, the carb was an Amal monoblock but was not the one specific to this machine. The rear shock absorbers were not the correct spec. It had a speedo and ammeter fitted- neither will be kept. The gearbox was a standard 'STD' spec - not correct for this bike, but I may keep it, as I will be using the bike on the road mainly. The handlebars- no surprise here, will be going. The petrol (gas) tank isn't right and will need further investigation. Otherwise the engine looks ok, it turns over fine, but it too will be coming apart and refurbed.
Here's a couple of images of the strip down.
An interesting project but, presumably, you are going to have to fit lights and silencers to it to use it on the road?
Hi Spaceman -
Thanks for your interest - lights and horn yes - not sure where I stand with the silencer issue. Might need to seek advice on that one. I'd rather not but may have to.
Due to the age of this bike, it will be exempt from MOT requirements, so not sure who will judge it to be too loud? Can you advise?
Here's a couple of images of what I'm aiming for as an end result.
Once stripped, the frame was found to be very straight. The only cause for concern was the lower left side tube where the kickstand was mounted. That section was torn up and had to be repaired and strengthened. The passenger foot peg lugs were ground off the swinging arm, it was then filed and polished smooth. The frame and swinging arm were then sent to the powder coaters.
Whilst the frame was away being painted, I striped the petrol (gas) tank down and was pleasantly surprised to find that it was an original tank that had been body filled and over painted during its life. The original paint colour could be seen on the underside. There were a few dents and bruises but I'm sure I can do something with it!
I stripped both wheels down and sent the hubs to a wheel builder in Norfolk. The hubs were cleaned and powder coated. The front hub was mounted in a 19 inch flanged alloy wheel rim and the rear was mounted in an 18 inch flanged alloy rim. I know the rear wheel was originally a 19 inch but I like the slightly 'squat' look of the 18's and there is a greater choice of tyres for the 18 inch. I also stripped down the front forks. Both fork tubes were bent and therefore replaced. The fork legs were powder coated and I reassembled with new bushes, seals, gators etc. I have put a slightly wider 19 inch tyre on the front; 3.5 instead of 3.25 and on the rear I have put a Pirelli 18 inch 110/100/18 knobbly. However, since I have fitted it, I think it is slightly too wide and will rub against the chain guard, so I've since bought a 100/100/18 instead; it hasn't yet been mounted on the rim as I'm hoping I might be able to make the 110 fit somehow. The frame is now back from the powder coaters and reassembly can begin! I have fitted a correct handlebar and replaced the headstock bearings. I have also fitted a pair of original Girling rear shocks. Here's some images.
OK, so we've now got a rolling chassis!
Next I bought a fully reconditioned Standard (STD) gearbox off the internet. I will keep my eye open for an original 'SC' spec gearbox, but I'm in no urgent need of that just yet.
Could anyone suggest a good sprocket combination (primary/clutch/gearbox/rear wheel) for this set-up? Aiming for good road manners really I suppose.
Here's a couple of images of the gearbox.
The engine is stripped down. The cases are in good order and have been bead blasted. The crankshaft is also in fine condition and appears to have had a 1st grind. The end play will be DTI'd before reassembly and shimmed if necessary. I've bought new big end shells (10 thou under), new main bearing, the crank bush on timing side seems to be fine. I've bought a new sludge trap and conrod bolts and new small end bushes. The barrel is in excellent condition and will be honed. The pistons are excellent forged items and 60 thou oversize. I will replace the rings. I plan to start the engine work/rebuild before Christmas. I plan to fit electronic ignition and my mind is thinking about the Thor system. If anyone could advise on this system or an alternative product, I'd be grateful. I wanted to keep the dynamo looking stock - hence the Thor system.
That's all for now folks. Have a good day!
Forgot to mention; I have also sourced an original spec rear mudguard/fender. I have stoneguarded the underside and now fitted it.
That's really all now folks!!
after going to all the trouble of finding original period parts for your project why go for electronic ignition. a manual competition k2f would suit your project and run great when overhauled with new armature and remagnatised body. no dynamo required either.
Hi Eddie,
Thanks for your response. This is a reason I have posted my project on this forum, in order to seek advice along the way. I will listen and consider all advice before I make my final decision. From the research I have done so far, I hear equally good arguments for each option. I am airing towards the Thor electronic ignition route for now as I have read about its reliability and concealed installation thereby not detracting from an original look. I suppose also Eddie, that it would be fairly straight forward to put it back to stock.
Thanks again.
i have rebuilt 2 magnetos using paul wolf exchange armature and re magnatised body with excellent results. i believe he advertises new mag armatures on the internet.
Thanks Eddie. I've looked him up on the internet. He seems to have an excellent reputation. The dilemma I have is that I have read mixed views over the subject of retaining the old magneto/ points system or swapping to electronic ignition. Some good, some bad views with each. I put electronic ignition on an old 1972 Yamaha RT2 and never had a problem with it. It was a hidden system and the bike looked stock. It's the reason I am drawn to the Thorspark. From what I understand, the system trigger is concealed inside the cap of the magneto and you wouldn't know it was there. Once installed, you get a good strong spark with no points issues to worry about. My earlier post in this thread was to seek opinions from anyone who has fitted this system to advise if its as good as publicised. This may help to swing my decision one way or another.
Converting to coil ignition means you need to find a suitable space to fit a dual coil and on/off switch and you become reliant on the charging system for your spark. With Thorspark you retain the original magneto armature bearings and oil seal so they may need to be serviced as part of the conversion.
Thanks Julian, that's what ive learnt from researching it, but do you have a Thorspark system and if so are you able to comment on its reliability compared to say, retaining the old mag/points system? If you do have Thorspark, where did you install the coils?
Hi,
A good mag. is hard to beat but the points and manual/auto advance retard is always going to be a weakness. The auto units are never going to have much control over the advance and manual would be a constant fiddle to match the advance to the rpm.
Using electronic compensates for this with a built in advance curve giving the most retard for starting and on the simplest ones, a linear advance to maximum. There is usually the need for a good battery as the advanced position is the default so a bit harder to start with a low battery. A coil is also needed.
I fitted Boyer Mk3 to my wife's A10 many years ago and it made the bike a lot smoother and it pulled better through the rev range. As a 'fit and forget' I did not have to do anything to the ignition timing.
The latest Boyer and the Pazon have a more retard making starting even easier and now do not need quite so much charge in the battery.
I suppose weighing up the cost of refurbishing a mag compared to the EI set up could be a decision maker along with how much is the bike going to be used?
Dave.
Hi,
The EI on my wife's bike in a mag replacement housing supplied by Kirby Rowbottom. I think that they do one that is basically modified mag so an authentic look is preserved. Boyer or Pazon should fit in these.
Dave.
I dont have Thorspark.
My experience with electronic conversion was not good but probably not typical..
My swinging arm A10 (49 years of ownership and use) suffered a sudden magneto armature failure almost 5 years back, I could not get a quick rewind so considered an electronic conversion with the better weather coming.
I considered 3 options.
First the cheapest, Thorspark but rejected it because it retained the main mechanical parts of the magneto and I did not think it worth doing a part job.
Second the BTH self generating electronic mag. The most expensive one. I wish in hindsight I fitted had this.
I settled for the SRM mag kit which replaces the armature with a shaft and sealed bearing housing and Boyer Micropower setup. That did not work out very well. It was as if some spiteful gremlin had taken over the bike. It was hard to find a suitable location for the unusual shape of the Micropower dual coil and when I set it up it continually kicked back ( it was not the way I had set the timing) when I tried to kick started the bike. It did run but starting was not reliable and you needed to kick it over fast or it would advance and kick back. Tried 3 different Micropower control boxes over a number of months with same result. When changed to Boyer Mark 4 setup it started and ran very well.
It is hard to find a suitable mounting for the dual output coil (different to the Micropower item but same as Thorspark type) space is limited, some suggestions made vaguely suggest "under the tank" Boyer supply a mounting bracket/heat sink for this coil as an extra. Using the bracket I fitted the coil in the tool box and needed to extend the HT leads.
To be honest with the problems with the Micropower and drilling extra holes for mounting the coil and on/off switch I was quite disillusioned and did not quite trust it and missed the simplicity of a magneto. So gave up on it and refitted the magneto with a rewound armature (with thanks to Andrew at priory Magnetos). Not missed a beat since.
Photos show the coil mounting I used with the Mark 4 Boyer.
Photos show the coil mounted in my A10 tool box.
You could consider a BTH electronic ignition. Self contained and needs no battery. I fitted one over 20 years ago to my Super Rocket. Performance and starting. tickover immediately improved. I have has to give it no attendtion at all since fitting it, indeed I forget its there!