The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: jhg1958 on 15.08. 2020 12:38
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My seat needs a bit of welding to restore the captured nuts. I will probably get a new cover at the same time.
But all is not as it seems. Although my bike is a 1961 A10 GF it looks like a pre 1959 seat with a dip in the middle and white piping. No problem I think I prefer this type.
The front bracket looks like a custom job. See photo. This was probably to cope with the loss of one of the captured nuts on the seat. This is fine but should there not be a lump of rubber part number 42-9057 here? If I use this bracket there will be no room without making the seat too high. Does anyone put a lump of rubber under the front bracket?
It would great to have the dimensions from a real bracket specifically from the slot to the the top where it bolts onto the seat. Mine is 1” from the top of the slot to the top of the bracket (underside of the seat pan).
The rear bracket is a bit of mess too. There is a newish one that sits on top of the mudguard as per 1954-59 models but this is a little low. I could make some new ones that bolt onto the side of the mudguard that has fixing holes anyway or else use some rubber to raise the seat 1/2 inch. Are both fixing systems equally good? If I make new brackets am tempted to use the suspension mountings as I need to weld the seat pan anyway. Does anyone know why they bolt onto the mudguard rather than the suspension?
Finally if I do get it welded, I was going to get studs welded rather than captured nut. Getting a nut welded square is more difficult than getting a stud plumb. I cannot see why BSA did not use studs anyway, what am I missing?
John
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Captive nuts are just that. Assemble everything on the seat pan, then just tack weld the nuts in place. Everything will fit as you have fixed the nuts in their final all tightened up position.
Car exhaust mountings, the sort with two threaded studs bonded to a rubber block ("cotton reels") make a handy and compliant rear seat mount, and a custom mount from the frame will be a better way to support the seat pan, avoiding extra load on the relatively weak rear mudguard. The original design, as always, is a compromise between the designer, production engineers and cost accountants......
Swarfy.
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But all is not as it seems. Although my bike is a 1961 A10 GF it looks like a pre 1959 seat with a dip in the middle and white piping. No problem I think I prefer this type.
John
Although the seats did have a dip in the middle, on some it is really pronounced. This is usually due to the rubber buffers fitted to the frame being wrongly adjusted (or missing). If the rider is of generous proportions (like me) the seat pan then bends in the middle. Sometimes done on purpose for those with short legs.
Occasionally the rubber buffers fall off - I superglued mine to the bolt heads.
I made some posts a while ago with comparisons of the various seats and if your bike is a 61 it should have a wider seat according to Leightons. This is what I have on my 59 and it feels more comfortable than the earlier type which I think you have. I ended up making the rear bracket to get it closer to the mudguard having tried the standard and RGS brackets.
Jim
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Well, this took about 15 seconds to find.
https://www.ebay.co.uk/itm/bsa-seat-bracket/324212295674?hash=item4b7c8f07fa:g:6F0AAOSwhQhednAm
Richard
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For an extra £1.80 delivered, they're available from CPC Eng in stainless fit and forget.