The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: paulbsa54 on 25.02. 2021 08:39
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Hello I have a 54 A10 with what I believe is a earlier rear mudguard. The rear light number plate holder slopes downward , could this of been how it was built or not ?
Cheers Paul
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Are you able to upload a picture?
This link should open a picture showing the back of my 1955 machine:
https://www.dropbox.com/s/9mhdaxwqt0ss5lr/CIMG0061.JPG?dl=0
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hi Neil .
your bike is fitted with what i know to be the correct mudguard , mine is from an earlier model . I tried to upload a pic but the file size was too big ?
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Paul Yes, No, Maybe!!
The 1953 Plunger models introduced the boxed in type of number plate mounting, which has a big hole for the reflector (up to 1955/56). This plate is flat, the top of the boxed pressing slopes down slightly and follows smoothly into the line of the rear light lens. The early S/A plate appears to be the same, then all change to a smaller hole to mount the reflector, but the light unit and box pressing remain the same. Part number changes because the number plate pressing changes to the small hole type. The last of the plungers would no doubt be fitted with the then current S/A mounting to rationalise parts use as supplies were run out for a soon to be discontinued model.
The later 564 lamp unit is more chunky, and to maintain the smooth aesthetic flow of the line, the later number plate now has an indent to angle the lamp and lens slightly downwards at the rear. Fitting this lamp to the early flat faced pressing results in the lamp cocking up, and can be seen on many restored machines in the absence of the correct 525 type lens, which has a distinct tapered shape.
Your bike could have a flat face part from the '53 change over, or a later indent type pressing, depending on how original and when the parts were made. The line of the boxed in section slopes slightly down in all cases, the lamp unit to suit will match this line.
GB's Emily has the later 564 chunky lens, and you can see the distinct change in the line from box pressing to lens. The earlier lens smooths this transition when fitted to the non indented flat face plate. Correct mudguard has centre rib and hinged rear section with a stylish flare to the lower edge. Also two small cutouts to the blade adjacent to the mounting points on the frame backstays by the saddle spring mount.
Swarfy.
Additional. With my speccys on it's hard to tell but the bike pictured below looks correct.
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mine is same as this one so must be correct ?
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Thanks Swarfy for the info very interesting . I think mine is probably correct it just looks different to the later type .
I will try and upload some pics , file size is too big off my phone .
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This is my bike with the mudguard in question
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and one more pic
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At first glance, that looks to be a later number plate assembly from a swinging arm machine on a plunger mudguard, not that I am a noted expert on tinware - or anything else for that matter.
You can see the angle on the 1951 Star Twin and the 1959 Gold Flash for comparison.
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It does look like the number plate is not correct , does anyone know the correct part number for my bike ? I did some research a while ago and 67-6885 looked promising .
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Paul. Maybe a trick of the light, but GB's rubber moulding follows a more angular line where the box top meets the mudguard blade. The boxed section here looks more rounded, not a true BSA style and the slope down looks slightly more than usual. Genuine original versions have a small cutout at the apex to allow the rubber bead to pass neatly over the central rib. Pattern parts generally don't and also do not always have the angled pressed indent for the later type lamp.
Whoops, it looks as if I got the first view wrong. Later shot shows the lens cocking up, not following the line. So looks to be the lamp is also wrong for true perfection. Lens 525 would do it. Also looks to have a later wide fin head on the early type thin fin barrel.
Plate 67 6885 would be a good choice, big reflector hole, but later 67 6830 (small hole) will do and it may be easier to source a suitable reflector.
First picture above shows the early open type mounting. The later bike has the chunky lens lying level, and has the lamp indent impressed boxed in plate.
Swarfy
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Thanks Swarfy , I also noticed that there is not much mudguard left below the lower number plate edge which was why I questioned the mudguard in the first place .
I did buy a new number plate a while ago and it is angular on top so I will have a go at fitting it . I do know there are no extra holes in the mudguard if a different number plate had been fitted so it's a mystery .
I have got the earlier head to renovate and fit at some point I bought it like this about 9 years ago but other projects got in the way it does run very well though .
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If you want better pix of my rear end *whistle* just let me know
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No Thanks GB *smile* your bike is a 55 so will be a bit different to mine
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Ah, an element of diplomacy there from Paul.
A spare cylinder head casting is better than money in a low interest deposit bond, ain't that so, Big Jim?
Swarfy.
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I have also noticed my mudguard does not have centre rib so it must be off something else . I would imagine getting a replacement will be like rocking horse 💩.
Are the Indian ones available any good would anyone know ?
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B and M Series plunger bikes share the same basic pressing, just with the addition of easily removed extra brackets. I did wonder if that guard started life on a Star Twin. Back in the day you could get new universal guards and cut and shut to fit. Probably still can now, but true time worn originality will cost.
With the interest in old bikes, ebay, clearing out Grandad's Shed etc there is more choice than ever before. Used guards are a gamble, shot blasting anything composed of atoms loosely associated is bound to lead to mental anguish.
Swarfy.
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shot blasting anything composed of atoms loosely associated is bound to lead to mental anguish.
That's another great thought for chairman wossnames little red book.