classic motorcycle forum
Motorcycle Discussions => British Bikes => Topic started by: codfish on January 17, 2011, 03:43:52 PM
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Hi, I need some help on this. Iīm restoring a A7 with interchangable wheels ( should be rigid but the old owner decided to fit a a plunger rear suspension). I had a hard time to find the right yokes since itīs a bit larger than the 1950 and so on. But now with the yokes assembled the wheels ( front and reaR)is not centered with the frame. I can only assume that the wheels should be laced withOUT the hub centered with the rim. I am right or Iīm doing something wrong again?I supose that the brake hub is right for this model.See photos atached.
Any help very much apreciated!!!
(http://img202.imageshack.us/img202/4851/img5486o.jpg)
By codfish25 (http://profile.imageshack.us/user/codfish25) at 2011-01-17
(http://img80.imageshack.us/img80/8364/img5487kw.jpg)
By codfish25 (http://profile.imageshack.us/user/codfish25) at 2011-01-17
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Hi codfish
I would seek advice over on the BSA A7/10 forum!
http://www.audioworld.net/BSA/forum/index.php
I have not come across interchangable wheels on a post war BSA???
HTH
John O R
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Don't know about interchangeable wheels on BSAs, but you should lace the wheel to centralise the rim in the fork tubes.
Easy enough to do in situ, provided there's a little scope for spoke adjustment.
Another good reason why amateur rebuilders should take loads of measurements for the wheel builder,or do it himself mounted in the frame/forks where it's intended to be used.
Not sucking eggs here, but are you sure that a back wheel can be used up front on an A10? Not saying you're wrong, but it's a new one on me.
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the first two model years of the A7 - 1947 and 1948 - used indeed interchangeable wheels. These consisted of the well known "crinkle hub"
mated to a 7inch drum with brake shoes of 1 1/8 inch width.
I am not quite sure if there are drums for this setup of different width. If there are, that could be the cause of your problem.
If the drums are correct, work from the back wheel to get your center lines right.
You first have to establish that the chain alignment is correct because that will determine where the hub center line has to be relative to the frame when the wheel is mounted in rear position.
Then adjust the rim center accordingly by means of the spoke length. Repeat this for the other wheel and then go to the front and check if the wheels are in the correct position there, too. If not, correct it by shimming on the wheel spindle accordingly.
Hope this helps
Cheers
Andy
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by the way, knock your wheelbuilder over the head first of all things!!!!! >:(
The big advantage of the crinkle hub is that you can use STRAIGHT spokes for increased strength with this construction!!!!!!!!
To use the usual spokes with the bent ends makes no sense at all!
Cheers
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[If the drums are correct, work from the back wheel to get your center lines right.
I stand corrected over the interchangeable wheels, but I'd have to disagree with this.
The front rim should be spoked to end up centralised in the forks (note "rim" not "hub") as the forks are symetrical to the frame tube/spine. The rear hub should be fitted with perfect chain alignment, then the rear rim position spoked to also align with the frame tubing or spine. That way the front and rear rims are in-line with each other and the frame centre line.
To leave the front until last risks the front wheel ending up not central in the forks, and how crap would that be? ;)
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I take it that what ever the ofset in relation to the front hub ends up being , the rear is the same or the intercangeable aspect is lost ? this may prove a problem if the correct position is not centeral to the hub as front to back and V/V requires rotateing the wheel 180 deg ( does that make sence ) the rear wheel needs to center with the frame spine reguardles of chain alignment ( as this is easyer to correct ) do both wheels need to be ofset the same way ? did BSA fit the drums on the same side ? ( unlikely i know but not sure )
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@Rex:
What you say about the rear wheel makes perfect sense. In fact, it's the same as I said, maybe just in better words.
But you can NOT begin with the front wheel! Of course you have to centralise the front wheel RIM to the centre line of the forks and the frame, respectively. But you can NOT do it independently from the rear wheel situation because you want to be able to use your perfectly centralised rear wheel at the front, too! That's what the idea of interchangeable wheels is all about after all.
So you start at the back and spoke both of your wheels identically so that their rims are central in the frame when your chain is aligned, and THEN you centralise your readily spoked wheels in the front forks and adjust their position via spacers or shims on the wheel spindle. Because only on the front position do you have a little latitude as to where the hub sits relative to the center line - certainely not on the rear where the position of the hub is determined by the chain line.
That`s why you have to start from the back!
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First of all , thanks Rex,wetdog, Andy and John for your fast answer!
So If I understand right I should first align the chain and then ajust the rear rim to the center of the frame and then put the front wheel at the rear and ajust the rim too.After that I should put the front wheel at the front and ajust it with shims to make it centered to the frame.
Andy there isnīt any straight spokes in Brasil but I will buy some from Uk to to make it right!
In my ignorance I thought the BSA A7 1947 wheels were assembled with the rim centered to the hub but I think even if I change that It will be "possible" to interchange the wheels as the rear brake drum is it the oposite side.(180 deg).
This motorcycle came to me almost burnt and in pieces to me so I had to start from scratch.Fortunately I got a lot of help from you felow bikers which do not have any problem in sharing information and a provision to answer my questions.
Thank you.
Antonio
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Yes, Antonio. That's the way I would do it anyway. And don't worry too much about the straight spokes; it doesnt matter all that much!
You did a very fine job so far and I am sure you will finish this restoration to your satisfaction.
The attached pic shows a crinkle hub with straight spokes.
All the Best
Andy
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In this part of the world, all spokes start out straight - I've watched a wheel builder neatly bend them all to the required angles - on a jig.
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Just a note of caution if you decide to centre the rims between your fork legs with the hubs as they are now.
The spoke flanges of the hubs are quite close together (i.e. narrow hub), so as you adjust the spokes to move the rim over towards the brake drum, the spokes on that side will reduce in angle - i.e. they will move closer to the plane of the rim. You need to take special note of the spoke tension if you are to retain the lateral strength of the wheel. The tension of the spokes on the brake drum side will need to be higher than those on the other side. Just how much higher depends on the difference between the spoke angles on the two sides. For example if the spokes on the brake drum side make only half the angle with the plane of the rim as the spokes on the other side, the tension of the spokes on the brake side needs to be about twice as great as those on the other side. When truing the rim laterally, this means that you if you slacken/tighten a brake side spoke by half a turn, you need to tighten/slacken its partner on the other side by only a quarter of a turn. (If you're adjusting radial run-out on the rim, it's still about 1:1 - all in the sines and cosines!)
Anyway, beware of moving the rim so far that the spokes on the brake side loose their "dish" (rim centre nears the flange on the brake side of the hub). Your wheel may collapse if give it a decent whack on the side! If in doubt, discuss with a professional wheel builder.
Leon
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. But you can NOT do it independently from the rear wheel situation because you want to be able to use your perfectly centralised rear wheel at the front, too! That's what the idea of interchangeable wheels is all about after all.
Well, yes, but I was rather ignoring the interchangeable wheel aspect as
a) riders tend to use use-specific tyres now (ie front or back fitment) rather than some sort of universal thing as was popular back in the hard-up 1940s. Probably a useful feature if the bike (and most likely, a side car) was your year-around transport, but not something anyone's really going to utilise now, I'd say, and
b) so many bikes after 60+ years have had incorrect replacement parts fitted; hubs, spacers, even complete wheels and forks may have been changed, so unless the builder is 100% sure that it's all as BSA made it, then it's better to start from scratch and treat each wheel individually, in my opinion.
Anyway, if you know it's all correct, why not then just build two "front fork centralised" wheels? Wouldn't that be the most convenient way?
Mind you, I personally wouldn't do that.... ;)
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hey Andy, it seems that your hub has a "cover" oposite of the brake, is it patern? both of my hubs dont have it , if itīs patern I will look for it as I always tought it should have a cover or something. Thanks for the incentive.
R, in Brasil all we can get made here are bented spokes for japaneeses.
Cardan, thanks for your advice, I will tell that for my wheel builder.
Rex, I agree with you, I donīt have the intention to exchange the wheels.
Thanks for all of you!!!
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Antonio,
I don't know if anyone sells this little hub cover as a pattern part.
But it should be easy enough to make one yourself from a piece of sheet metal or you could even turn one from aluminium.
That should be nice looking when polished!
Cheers,
Andy
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Hi there, Probably should have done an introductary post somewhere, But I guess I'll get around to that some time soon!
I noticed this thread upon searching the net for 1947 and 1949 A7 info. Was quite alarmed when I saw these pics, as it was only yesterday that I put mine back together. (currently restoring a 49, but also piecing together a '47 that the old man is doing as well).
The '47 I have has interchangeable wheels, and I can tell you I have the original ones here pulled off the bike. I am not in the shed right now, but will take pics, and show dimensions tomorrow sometime.
I do know that both the wheels ARE identical, and if you put a straight edge from the spline side of the hub, to the outer edge of the rim, this should be all straight. ( not too good at explaining this!).
Also, not sure if it is optical illusion, but the pictures appear that the fork are tapering in.. (wider at top), You realize the '47's have a wider triple tree set up? It appears you have the correct top one (can see the wider handle bar clamps), is the lower clamp the same width? It should be, otherwise the forks will taper in (Not parallel)
In regards to "Shimming" front wheel... I don't think that is possible. The front brake plate should have a shoulder that goes into the fork tube (Primary side of bike), and then the other side should have a bush that goes into the fork leg, and spacing it correctly. What you have in the pic looks correct in that matter, but there is 2 different length bushes, one for interchangeable wheels, one for regular wheels.
AND I think the interchangeable wheel front axle is slightly different to the regular wheel axle...
Not here to poke at your work, just thought I would offer some knowledge! I will take some pics tomorrow, and also see if I can take pics of original parts list/manual that will back it up for you.
Cheers, Brett.
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ok, almost forgot about this, but took some really quick pics this arvo before locking up..
Here is the difference i was talking about in the triple trees..
(http://a3.sphotos.ak.fbcdn.net/hphotos-ak-snc6/181509_1802114262651_1533662948_31891577_6952823_n.jpg)
(http://a6.sphotos.ak.fbcdn.net/hphotos-ak-ash1/182773_1802114502657_1533662948_31891579_5656636_n.jpg)
And the alignment of front AND rear wheel...
This is a straight edge running from the spline side of the hub.
(http://a7.sphotos.ak.fbcdn.net/hphotos-ak-ash1/179885_1802114582659_1533662948_31891580_113581_n.jpg)
Mine is not in the bike now, So I can't take any pics of it all assembled, but I can assure you, I have had wheels in the bike and fenders on it to make sure of their alignment. I am in a lot earlier stage than you, as I am ony piecing all the parts together now, and making sure they all fit ;) I generally do that with most of the bike (mok it all together), and then once I know it all fits and works, I send everything off for paint/ powdercoat, chrome etc. etc.
Here is the '47 as it sits now, and you can just see the '49 sitting behind it.
(http://a8.sphotos.ak.fbcdn.net/hphotos-ak-snc6/182629_1802115022670_1533662948_31891584_2629936_n.jpg)
Hope this helps, Let me know if you have any questions, or need any measurements etc.
Brett.
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Hey Brett, thanks for answering my topic. After all the help from the other members I changed the "aligment" between the hub and rim like you said with the ruller , worked well with the rear wheel but with front I had to add 8 mm more to make it centered with the forks and frame. Yes, I had a lot of trouble finding the right yokes ( seems that only that year or so had the longer yoke(1 inch app.).I only found it in USA ebay ( believe it!!) after consulting every shop in UK I found In the Classic Bike guide magazine. I have a parts list for the 1947 year but some itens in Uk ebay donīt have part numbers listed.
Since you asked , I would like imensely if you show some pictures of your filter box. In 4 years I never saw one to sell, so Iīm planing to " build" one for my beeza.For now I just have bad drawings from my parts list.
I imagine it has the same form of the oil tank by side but the rest I dont have any reference.
I took some pics after I changed the wheel ( changed the spokes but still from a honda with a litle bend).
As you will see I bought this bike in pieces and as a newbie I didnt notice the supension adaptation at the rear wheel. At some point the previous owner got tired buns and changed the rigid to a plunger using JAWA parts ( as a friend told me).
Andy I had the cover made , show you latter how it became.
Anyway as you see in the pics I still have a lot of work to do and parts to find.
THank you all for your great help(http://img834.imageshack.us/img834/9052/img5490b.jpg)
By codfish25 (http://profile.imagesha.ck.us/user/codfish25) at 2011-02-12
(http://img19.imageshack.us/img19/4002/img5492w.jpg)
By codfish25 (http://profile.imageshack.us/user/codfish25) at 2011-02-12
(http://img713.imageshack.us/img713/9260/img5494r.jpg)
By codfish25 (http://profile.imageshack.us/user/codfish25) at 2011-02-12
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Sorry Codfish, I have only just got back on here and read your reply.
Ill take some pics tomorrow of the airbox, and try get some basic dimensions for it as well for you.
PS: Pretty sure you will find your front mounts for the rear fender are upside down... ;)
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HI Brett, Iīm late too to answer you. I managed to fix my weels but now Iīm fixing the gearbox. I will really apreciate if you send info about the filterbox. I have another one that I will post a photo to see if someone id it to which Bsa it belongs.
Many thanks
Antonio
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ok, Here's some quick pics I have just taken with my iPhone, Let me know if you would like the pictures in greater detail.
If I wast to make this, I would make the main mounting bracket first (you may be able to raid it of another air filter box/ battery mount?) and then go with the tin work to shope it the same shape as your oil tank, and then curves to fit around frame.
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Here are two more pics I had of it, and finally, where my '47 (Red), and '49 (Black) are at now...
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Hi Brett, excelent photos, I think I can manage to make a new one from it. Thanks a lot!
by the way, if itīs not too much trouble for you, can you show me the mount bracket for your stop switch?
You are bulding a red BSA? thatīs a new one for me, I canīt say much as I painted my tank with green... hehehe
good luck witrh your restorations. I will post a photo of my filterbox, problably from other BSA then mine. I may even trade it .
Antonio
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Here goes my actual filterbox, diferent from you it seems. If anyone can id it I would apreciate it, and if anyone have a filterbox like brettīs I can exchange it with this one.
(http://img98.imageshack.us/img98/6717/filter2p.jpg) (http://img98.imageshack.us/i/filter2p.jpg/)
(http://img834.imageshack.us/img834/8435/filtervm.jpg) (http://img834.imageshack.us/i/filtervm.jpg/)
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Yours does appear very similar, but from what I can see, would not "Wrap" around the frame (At front). when mine is mounted, my oil tank, and air box meet at front... Will try take a pic of my black one which is mounted to show you (slightly different shape, but same idea)
Glad I could be of help :)