The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: Steverat on 20.11. 2018 19:31
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I had an early plunger mudguard repaired by a friend, with considerable effort. Offering it up to the bike I see the stays can't reach. Definitely not a Heineken moment. Does anybody know why?
steve
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Mudguard looks ok. I'm pretty sure the stays on my bike do not have that kick-up. This is from t'interweb.
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Agreed, the stays look wrong.
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Yes I can see it now. They have been bent in two places, downward when they bend away from the plungers, then more sharply upward lifting them above the bracket at the back of the guard. Now I need a tube bender! Those things are too stiff to be bent by hand.
Thanks for your observant comments.
Steve
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Hi Steverat, as others have mentioned, the stays are modified/bent. Attached is a pic of how they should be. Also note, the top mount should have the "Bridge Piece under the mudguard and the stay mounted to that. NOT mount the stay directly to the outer mudguard.
I also realise this fender is different being that is a Superflash, but the idea is the same and I don't have a pic of another plunger handy
(https://mikesclassiccyclespares.com/wp-content/gallery/home-images/DSCF4354.JPG)
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Here's mine.
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Hi Steverat, as others have mentioned, the stays are modified/bent. Attached is a pic of how they should be. Also note, the top mount should have the "Bridge Piece under the mudguard and the stay mounted to that. NOT mount the stay directly to the outer mudguard.
I also realise this fender is different being that is a Superflash, but the idea is the same and I don't have a pic of another plunger handy
(https://mikesclassiccyclespares.com/wp-content/gallery/home-images/DSCF4354.JPG)
Thanks Brett.
In your picture the stay appears to be in two parts, interestingly. Yes on Josef's bike the top end of the stay does go to the bridge piece under the mudguard, so that's alright. It was the lower end I was worried about. As the bishop said to the actress.
Like your bike too. Very smart.
Steve
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Here's mine.
Nice to hear from you again, thank you. BTW the "new" gearbox is being used in the rebuild, the crank cases are in reserve now since I managed to get my hands on a pair which are matched. Not that it makes any difference to the fit/concentricity of bearing housings, as we discussed at the time. Or Does it??
Steve
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Steve, You may have a bigger problem than you think. The mudguard looks to be slightly too far back and needs rotating forwards. The frame lugs are fixed so these are obviously in the right place. The problem could be the mounting strip on the guard which should be riveted to the blade with the mounting holes lying centrally in a small cutout on the edge of the blade. There is a cylindrical spacer each side from the mounting strip to the frame lugs. The spacers do not mount directly on the blade but onto the mounting strip. The strip may have been moved, or shortened. Next check the lower mudguards stays, the two metal strips that go between the lower front of the guard and the frame footrest support. They should be fitted with the small right angle bend pointing down. They are left and right handed. The front of them should be horizontal, then a bend slightly upwards to enable a snug fit on the guard. The guard looks to have the right holes, but looks too short or too high at the front lower edge. Try fitting the oil tank to see how close the guard is to the back of the tank. If these checks are OK, then raising the middle of the guard could be the answer.
The mounting brackets have been butchered as you already know. The flattened portion at the top looks longer than usual, so may not be a genuine part. The simple answer could be that they are not holding the guard high enough. Fitted correctly the upper tubes should be at least vertical or inclined slightly forward following the line of the plunger units to the point where they join the guard and are generally fitted inside the mudguard blade. If you have a dual seat, use the seat and its mountings to get more of an idea where they should end up. These support tubes are tough, but bend successfully with a bit of heat as long as you avoid heating and disturbing the brazed on lug.
The bracket lower rails should be straight and be horizontal/slightly down to join the mudguard rear mountings. So, you may find you have the right mudguard but it has been amended badly over the years. Put the wheel in to see how it looks and whether the guard follows the rim. The hinged tail piece looks in the picture as if it could be tweaked so the bottom moves a little further forward as well.
Roy Bacon's book on BSA Twin Restoration, published in 1986 is a great source for you if you can get hold of a copy. It has lots of pictures of what you are aiming for.
From experience it is always better to build in the rough, then dismantle for final finishing and then rebuild for perfection without accidental damage to your expensive paintwork.
Be interesting to see what you find. If anyone can do some measuring that will certainly help solve the problem.
Swarfy.
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I had thought the same thing Swarfy, but looks like a can of worms and without standing there looking an pointing, it's hard to explain.
As for the stays on the SuperFlash, yes the Right Hand Side is 2 parts (Hence why I mentioned slightly different)
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Steve, You may have a bigger problem than you think. The mudguard looks to be slightly too far back and needs rotating forwards. The frame lugs are fixed so these are obviously in the right place. The problem could be the mounting strip on the guard which should be riveted to the blade with the mounting holes lying centrally in a small cutout on the edge of the blade. There is a cylindrical spacer each side from the mounting strip to the frame lugs. The spacers do not mount directly on the blade but onto the mounting strip. The strip may have been moved, or shortened. Next check the lower mudguards stays, the two metal strips that go between the lower front of the guard and the frame footrest support. They should be fitted with the small right angle bend pointing down. They are left and right handed. The front of them should be horizontal, then a bend slightly upwards to enable a snug fit on the guard. The guard looks to have the right holes, but looks too short or too high at the front lower edge. Try fitting the oil tank to see how close the guard is to the back of the tank. If these checks are OK, then raising the middle of the guard could be the answer.
The mounting brackets have been butchered as you already know. The flattened portion at the top looks longer than usual, so may not be a genuine part. The simple answer could be that they are not holding the guard high enough. Fitted correctly the upper tubes should be at least vertical or inclined slightly forward following the line of the plunger units to the point where they join the guard and are generally fitted inside the mudguard blade. If you have a dual seat, use the seat and its mountings to get more of an idea where they should end up. These support tubes are tough, but bend successfully with a bit of heat as long as you avoid heating and disturbing the brazed on lug.
The bracket lower rails should be straight and be horizontal/slightly down to join the mudguard rear mountings. So, you may find you have the right mudguard but it has been amended badly over the years. Put the wheel in to see how it looks and whether the guard follows the rim. The hinged tail piece looks in the picture as if it could be tweaked so the bottom moves a little further forward as well.
Roy Bacon's book on BSA Twin Restoration, published in 1986 is a great source for you if you can get hold of a copy. It has lots of pictures of what you are aiming for.
From experience it is always better to build in the rough, then dismantle for final finishing and then rebuild for perfection without accidental damage to your expensive paintwork.
Be interesting to see what you find. If anyone can do some measuring that will certainly help solve the problem.
Swarfy.
Thanks Swarfy and Brett
I tried putting the front lower brackets on - they fit fine and pull the front of the guard forward slightly but not much. About 5 millimetres. I'm pretty sure the mounting strip with its cutout holes are in the right place, if not they were moved a long long time ago, and there is no sign of that. I made a couple of spacers to fill in the gaps there where the "cotton reels" should be.
Nick has remade the area around the hinge because it was so badly corroded, so I think that may be the reason why the back of the guard looks too far back.
I also tried putting the seat on. I think the front should mount on the point holding frame and rear subframe together, is that right? Having trouble getting the rear mounts to coincide with the holes where the tops of the stays come up. It doesn't look in the right place, it doesn't follow the line of the mudguard the way I'd like...
Apart from the aforesaid rebuild in the hinge area, I am reasonably confident that the holes and rivetted-on brackets on the guard are all in their original positions. There is no sign of them having been moved.
Here is a photo with the front brackets and the seat on. Please take a look.
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You might find the nose of the seat mounts on the lug above where you have it....I think the rear lift- up bit looks to roll around too far.... maybe optical..... and maybe someone else can give a overall measurement to , or from the vertical to the join....I can't because mine had been chopped just behind the vertical brace
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Steve....You are not far from getting it right. The seat looks to be relatively new, so is this on an original pan or a pattern part? The cut of the lower edge looks different, and again the seat looks to be low at the back and also positioned just a bit too far to the rear. Check other bikes on the internet for the appearance of the gap between the lower seat edge and the frame tube. The seat brackets look OK and the correct parts fitted correctly. Swapping the rears side to side is also worth a try. The front will only fit one way because of the three hole fixing. On my bike the front seat bracket was a flat plate with three bolts to the pan, but with two extensions forward to mount on that vacant lug which is used when a single seat sprung saddle is fitted. This lug sometimes has a grease nipple, hence the threaded centre hole on some frames. This bracket looked to be a homespun item. I preferred it as it allowed easy removal of the seat without disturbing the stubborn stud holding the frame together. Your front looks like the genuine part, but if the seat and bracket are pattern parts , here comes another source of error..... all the mounting holes in the wrong place.
Mudguards are relatively expensive, I would be inclined to stick with the mudguard you have, mount the fuel tank, position the seat where you think it looks right, then make a new front seat mount to preserve the ( possible) original bracket for the time being.
Looks to be that those rear stays are very wrong, so you have nothing to loose (except the nice finish) by bending them back to normal shape and extending them as necessary to get everything looking right My feeling is that they are not supporting the mudguard high enough. Once it is set up to look right, that no longer attracts the adverse attention from the purists and you have done the best with what you have.
Brett... Thanks for your consideration of the situation, too right its a big can!
duTch...Sure looks strange, as you say hard to tell so measurements from a known good 'un are what we need.
Swarfy.
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Steve, the upper lug is for a saddle; you have the correct place for the dual seat. There is quite a lot of adjustment in the seat brackets.
Looks like you are not far off sorting the guard. The hinged part on yours is slightly open. You should be able to fettle that. Get the stays straight and bob could be your uncle.
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Are these pictures helpful?
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Excellent thanks. How does this look?
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Steve....Well done. I reckon that's pretty good, you can be well proud of your efforts. Looking back at your earlier posts, was that the original mudguard that came with the bike?
Swarfy.
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Swarfy
Tthanks for the praise I don't deserve, Nick my good friend sorted it for me.
Here is a picture of the mudguard which came with the bike. I don't know what it is. Any idea?
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Steve....Hard to tell, but it looks to be a genuine guard , from the rolled edge at the chain indent, rather than a generic guard modified to fit. Then again, the flair is missing under the rear number plate, the rear section has a bolted rather than riveted mounting and I cannot see a central rib or hinge. I have seen later machines without the rib, but don't know if or when the guard changed.
Someone will be along with the answer.
Swarfy.
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You are right Swarfy there’s no rib and no hinge.
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Either has mine... *????*