A  1949  BSA  A7 500cc  Mark 2   Long Stroke  Duel Carb  Star Twin

Just looking through the bikes for offer on Ebay and I stumble upon this. I had not been looking for another bike to purchase at all but because a friend had successfully purchased and sold a very nice A7 for a handsome profit, I had dreams of doing the same. It really is amazing how ebay can run away with you, the wife and I sat and discussed this and I think she was more enthusiastic than I was, I could see pound signs scrolling in her eyes. So plans and pennies were hastily thought up as the hours started to count down towards the auctions end. The end time was Sunday 19th October at 22.53 and it was only around 8pm that evening when I first discovered this bike!

I was amazed at the fact that no one else bid that evening and seeing that there had been nine other bids earlier in the week, I quite thought that it would go for beyond what my maximum bid was, which was 2,201.21. It was won for a Princely sum of 1,851.00 and resides at Grimsby in North Lincolnshire. My new Motorcycle adventure now begins...


Description and photos from the selling page

Here we have for sale a BSA A7 500cc Mark 2 1949 Long Stroke Plunger 

This bike has been stored in a dry shed for 14 years and kicked over on a weekly basis so the bike has not seized up

The tank is in need of a re-spray and inside the tank there is a little rust due to the tank being empty

The number plate is not the original as the previous owner had the bike re- registered with new ones

Some years ago I had many parts re-chromed I have also replaced the rims & spokes

The gearbox & mag was overhauled

The bike has had new tyres both front & rear

The engine sprocket has been replaced & also the wheel sprocket

There is new plunger spring covers

The bike will need a service before actually being run all work has been done a good few years ago

Unfortunately I no longer have the time to spend on the bike and its seems a shame to keep it locked up in a shed

Hopefully someone can have the bike up and running and put to some good use







So there we have it! Not bad eh?

All that now remains is for me to go and collect it which is to be tomorrow mid day sometime. I am now starting to get nervous, will it be a bag of old nails? rattely and worn out needing hundreds of pounds spending on it? Or will it just be a classic bike collectors dream come true? We shall have to wait and see.

I'm Back!

Oh what a heck of a long ride to Grimsby and then back again... Yep! I got it, first impression? well... yes okay, what can you really expect from a 59 year old bike and for the price? The only bad thing that seemed to stand out was the 'Amateurish, new brush, B&Q paint finish with a handful of sand chucked in' (Hey I'm a time served painter & decorator dont'cha know?) Shame really but! that prevented rust & rot and I can easily rectify the paintwork at a later date. The chrome looked okay not the best, but good enough. The seller was a decent enough chap and I think he seemed quite genuine. It's easy to think that someone is giving a load of bull when selling but l later looked and found that he probably was not giving as many porkies as I first imagined. I really did want to start the bike up to check the big end bearings, he was okay about that but we did not have any oil only some petrol and I felt that he might have been a bit miffed of me insisting it be running and not taking his word for it that it was all okay, so I took the gamble to take it as it was. The time soon came to part with cash and strap the bike on and along with a few other bits and pieces we were ready to go. The owner was soon seen in the rear view mirror waving with a tear in his eye as his old faithful machine set off for her new home. To be honest... The guy did not really seem the type of chap for riding these old clunkers, him being the owner of much more modern, faster Hondas but, he probably had a lot of fun just tinkering with the machine at least, and that's what its all about. (Damn... hope he isn't reading this! Laughs...)

Home at last and off the trailer and straight into workshop and onto the work ramp/table lift. No problems with the transportation and nothing tried to jump off to run back home. My first job before getting it started was to give the engine a good looking over. I had the timing and primary side covers off to look inside and to see if all was well. There was only a tiny amount of oil in collected places and this had sort of dried out into a treacle syrup like mess but was clean, in short the oil was dead and was a good indicator of the bike not having been run for a long time. I also saw that there was no carbon deposit on the piston tops and soon I came to the conclusion that the bike had not been run at all so my confidence grew that I had a good rebuilt engine. All nuts and bolts were good and not damaged, most had nice washers and spring washers on, so that the work looked like it had been done with care. I found that the primary chain and rear drive chain were a bit too tight so loosened them off a bit, also the engine sprocket cush nut was not done up really tight as it should be and was loose against the split pin, this is a common mistake, the nut MUST be done up tight to hold the main bearing against the crankcase or the crankshaft will float back and forth when running causing wear. Some pictures follow of the 'untouched-by-me' bike.

Saturday Morning...

And after an update of this web page from yesterdays thrill I am soon ready to venture back out to the workshop. I could be running the engine later on after topping up with some cheapish 20/50 oil to clean through the engine. I normally use a good straight 40 oil with no modern paper filters, regularly changed after 1,000 to 1,500 miles and everything should be fine. I am going to treat this bike as a newly built machine and give it the usual slow riding running in period and then slowly build up speeds as I get to the first thousand miles... Enough typing! I need to get outside...


Okay... After a seriously crippled leg the bike WILL not start, just the occasional pop back through the carb is about the best it can do. I tried different plugs, the compression is very good indeed at 125 on both cylinders. Plenty of petrol everywhere, reasonably good spark at the plugs. I looked at the position of the valves in relation to the position of the points on the camring, timing seems to be correct although not checked it precisely. I do suspect though that there might be just a slight amount of clutch slip, my other bikes hate this and often will not start if they slip. I shall have another go tomorrow when leg has had a good nights sleep. I aint given up yet, it will go when she has settled in and made friends with the others. 

Sunday... All day

Right well, I spent the whole day cleaning the carburetor today, completely stripped it down and cleaned it all inside and out. Even the copper pipe from tank to carb reservoir, I found it had a very small hole and this was responsible for yesterdays petrol flood all over the place. So I am now confident that the carb is of no trouble and will work perfectly. After fitting it came the marathon kicking exercise again and I even eventually took apart the clutch and inspected that, putting it all back together again but tighter than what it was before so there was no slip while kicking, it had made no change. It now leaves stripping down and inspecting the magneto and timing which is what I have been suspecting all along. Although there is a spark there, it can diminish if it is too weak and under compression. That will be my job for tomorrow, if I should find the armature to have original windings then I'll most probably send the maggie off for a rewind and new capacitor/condenser. This might make a nice bike ride down to Towcester to see Tony Cooper who is supposed to be the best in the country. We shall wait and see. But......... I WILL get that bike running!

Monday 27th October...

Got the magneto off today after agreeing with a friend that the timing looked way out. I completely stripped down the magneto apart from windings and cleaned it up. I found one carbon brush had fallen out of a pickup and was only picking up current via the spring, the other lead at the plug cap end had been screwed on missing the center wires, there was also grease behind the brass contact plate where another carbon brush makes contact, I think this is the earthing brush. The outer points housing was found to be fitted upside down allowing oil to run out and round the inside of the points house, under the cam ring there is an oil channel where a felt strip is soaked allowing oil to siphon up to the inner side of the cam ring allowing lubrication to the points arm. I found also that there would be an additional benefit to solder the wires to a small brass disc at the magneto leads end where the leads are screwed into the magneto. Tomorrow I shall refit and re time the ignition and hopefully the bike should start first kick, I'm confident that it will. The windings look like they may have been rewound 15 to 20 years ago, they are certainly not Lucas original, again hopefully if they have been done properly they should give no problem for a few years to come, but the blip on the contacts suggest that the condenser/capacitor might be on its way out. Normally they are replaced when the windings are done as they are impossible to get at unless the windings are removed.

I was surprised to learn that the inner timing cover did not allow the auto advance mechanism to be taken out like on the later A10s that I have. I will need to ensure that the taper is very clean when coming to refit the magneto. The person who last timed the magneto had let the magneto slip when setting it up. It is very easily done and the secret here is to give a sharp tap on the nut that does the advance mechanism up this gives a bit of a firmer hold while tightening up the nut, It is a very delicate operation. Next update tomorrow night!

Tuesday 28th October...

Well... It RUNS! yep it was the magneto all along. Timing it up was a bit of an intensive effort, it 'has' to be right. It's always a worry with the timing slipping on the taper but as mentioned before... a light tap on the taper nut seems to give it that initial 'start off' I also gave to dynamo a strip down and look over while the timing cover was off and re fitted that, it just needed a cleaning down and possibly a 'flash' (to energise the windings) tomorrow during daylight. The cyclon gel type battery came this morning so I dug out the old battery inners and fitted the new battery into that. The bike, according to manual is a negative earth so I'll go along with that as original. All the lights work, no broken or blown bulbs, perhaps I ought to look over the mechanical regulator before the dynamo kicks in or all the bulbs will blow if too much charge is output at high engine revs. Well, its been a great day with a very satisfying evening when it DID literally start first kick after two priming engine turns to allow mixture flow to combustion chamber. (Hey I'm using technical terms now!)

I was pleasantly surprised at how different the A7 sounds and feels after being so used to the two A10s I have. It does seem very smooth and I would imagine very sporty when riding. I am also looking forward to feeling what the plungers are like. I'm beginning to think that this could very well become my 'best' bike! Well, a good day tomorrow and I should be nearer to MOT time possibly riding the bike this very coming weekend. Must get some photos on here again tomorrow.

Tuesday 3rd March 2009.

Just as I now feel like updating this page as so much is happening, I thought it's time to start a fresh page! Click on the appropriate link here to take you to the... 

Star Twin Page Two.


Return to Home Page

Guest Book Comment?