The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: imustbemad47 on 10.02. 2020 14:11
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What i would have given to have had access to such a mine of information back in 68 when i managed to blow up my first BSA A7SS. Back then it was Pride and Clark of Brixton that was my oraclle! Since then I progressed to an A10 which I converted to a tribsa with a T110 engine. Its maiden voyage was a trip to Biaritz where i had agreed to meet my then girlfriend who had hitched there a week earlier. Without sat nav we met up as agreed on the due date and drove to the basque together, returning home a week later without incident, except it rained all the way from Bordeaux. That girlfriend married me a few years later and we've been together ever since.
However............
I have taken the plunge and recently acquired an A10, which turned out to be a bit of a hybrid with a SR engine (beefed up/converted by SRM back in '91) but with a much earlier half hub set of forks . Interesting! It seemed a good idea to fit a full width 8" hub for a TLS installation as fitted to some later Triumphs; but nothing is that simple. It would appear that the fork sliders will not accomodate a FWH so will probably need replacing. Ive read that the Triumph spindle will need machining to accomodate the bottom bolts and that the BSA 8" hub is designed for 1 1/8" shoes not 1 5/8", which begs the question whether or not new sliders can be used on the old forks anyway without incurring further expense , other than welding /extending the lug to slot into the brake plate. Try as i may i cannot find a thread that allows me access to see what other members have done to achieve the TLS end result from such a suspect foundation.
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Welcome, you have been around BSAs nearly as long as me, somebody here will help, I have TLS set up on my Super Rocket which was made especially by John Tickle
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i read with interest your posts on this. Motivated me to believe anything is possible and that what i planned was half sensible. Now i am beginning to wonder whether stopping power gained will be worth all the grief. But i don't give up so easily so will continue to research. thanks
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Hi
It would be easier and less hassle to fit a TLS to the 8inch half width hub
This brake is regarded as probably one of the best BSA fitted
Of course there are a couple of different versions of this hub too, the early Flash and "M" steel , then the cast finned Goldie one and the later A65 looks the same but has a deeper drum for wider shoes
Apparently, the SLS brake can be further improved by reversing the lever on the hub to face forwards as on the Daytona race bikes (photo)
Changing the sliders would also probably mean changing the mudguard or its mountings , then the cost of the wheel and Triumph 8in. tls brake plates are not cheap either
Phil Pearson sells a repro "Taylor Dow" tls for the single sided 8in. hub and also for the 190mm full width hub
www.bsagoldstar.co.uk
Not cheap at £635 but it doesn't go far on doctors bills *eek*
John
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Welcome aboard! But became less of an introduction than a tech topic, moved to correct board.
Post a new introduction :O)
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It would be easier and less hassle to fit a TLS to the 8inch half width hub
Which is what I planned to do with mine, however upon acquiring a TLS found the shoes too wide for the 1/2 width hub (1956 A10) so can you get narrower shoes or a slightly wider 1/2 width hub ?
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The half width 8" brake is BSA's best. I would stick with it. If it doesn't seem up to scratch, get the shoes relined a proper outfit (Saftek or similar).
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Hi Kickaha,
so can you get narrower shoes or a slightly wider 1/2 width hub ?
Without photos too see what you have its impossible to say
All I can say is that A65's with the 1/2 width hub had wider shoes / deeper hubs than the Gold star one
The extra depth is inside the spoke flange of the hub
I'm not sure what width were fitted to the 441 singles that look the same in photo's
John
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The up to 1965 season 8 inch half width hub takes 1 3/8 wide shoes.
The 1966 on take 1 5/8 wide shoes.
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Best off swapping the whole shebang from sliders down... TLS hub and brake and sliders from the early A65. The mudguard mounts may be an issue, but as the brake won't be original you don't need to stick to original mudguard mounting arrangement. I think one of the A10 sliders will work but a tab needs welding on to the RH slider to slot into the brakeplate stop.
My sliders are the ones with 2 studs welded on the inside of each for mudguard mounts and bolt up caps for the spindle.
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Apologies to imustbemad47 for the thread hijack, this is what I currently have, the TLS shoes are 1 5/8, I would like to stay 1/2 width if possible even if I have to find another hub
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Yeah but maybe explain a bit more fully!
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You might be trying to do the impossible. Get the right hub to fit that brakeplate. It's '68 - '70 BSA and Triumph isn't it? Then the sliders to fit that.
IMHO of course *bright idea*
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From what has been said about the half hub forks it would appear that to achieve what I want will involve replacing the fork sliders with the later early sixties A65 ones which appear to be a straight swap provided that i can remove my originals. I have a sneaking suspicion that it is going to be easier said than done having read a number of useful posts about poor quality tools which are hardly fit for purpose so that I will probably have to replace the oil seal holders (which are in poor condition anyway) with SS. Can the 8" BSA FW hub be swapped for the Triumph 8" FW hub?
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Oilseals and fork bushes appear common to A10 and A65, so existing stanchions can be retained. If you don't already have a seal holder removal tool, invest in your chosen seal holders and make your own tool to fit them, this is to make sure the tool gets a good purchase on the relatively small area where the tool locates on the holder. Plenty of images available to show the official tool.
A little heat from a hot air gun will help getting the original holders off the sliders. Replacement holders need to be supplied by someone with a good after sales service....problems with poor thread profiles have been reported and a first time fit is not always a cert. Get the correct sliders and matching holders for the chosen front hub/brake assembly, as welding tabs on sliders risks distorting the slider bore, rendering them useless. Draganfly parts diagrams are worth a look.
Swarfy.
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thanks swarfly. So far so good. Mudguards, wheel and brake plate carefully removed and time for a pause for absorption! Forgive my ignorance but do I have to take the forks off to remove the oil seal holder?
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Yes full fork removal required, you need to remove top nuts which also allow filling of oil.
Pinch bolts to fork yokes need to be slackened, you may have tap the stanctions to release them from there taper within the yokes, best to screw back in the top nuts a few threads and give them a tap with soft hammer. The seals are held in by a circular clip, with shims on top of the slider bush.
Reaasembly is a challenge, the clip can stress you out.
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To add to Billy's excellent summary, here are a couple of hints.
With the lower yoke pinch bolt removed, force the gap open with a wedge....usual tool is a flat blade screwdriver hammered in. Undo the top nut a few turns, 1-2 mm above the top yoke will be fine, then shield the chrome finish with something solid. Now support the top yoke with your third hand and smack down with the mallet onto your nut shield. This should free the top of the stanchion from the top yoke. Remove the top nut, the fork leg complete with spring will then pass down through the bottom yoke.
The oilseal holder then simply unscrews, (in the best Haynes tradition it can be a right pain) using your new tool, leaving the top bush exposed, retained by the pesky wire circlip. With this little devil removed, the fork leg, oilseal holder and bushes then draw out of the fork slider. You may find some shims under the circlip to take up any gap between circlip and bush.
Replace the leg, less slider and spring, back into the yokes, and tighten the lower pinchbolt. This will keep the leg still to enable the lower bush nut to be undone. Slide off the bushes, the circlip and the oilseal in its holder. With the leg then removed, check it's straight by rolling on a flat surface.
Reach for a well deserved beer.
That's the easy part. The second leg will be even easier.
Have a look in the frame and forks section of the Forum as there is a lot of experience noted regarding circlips, shims and the later collapsible spacers, which overcome the problems associated with the circlip and shim design.
Apologies for unintended humour, but laugh now 'cos putting it all back together can be a struggle. Beg or borrow a broom handle, all will be revealed in the next instalment. Billy's last words ring true.
Swarfy
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i must be super strong, when I put my fork legs back in I manage to push them up into the bottom yoke then ram them up into the taper enough to get the top nuts started, I even managed this when it had side car springs *work* I also use a strap to undo seal holders and hand tighten them.
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"Can the 8" BSA FW hub be swapped for the Triumph 8" FW hub?"
Yes.
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Yes Jools but you have to use the BSA axle.
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I gambled that the hubs were interchangeable and acquired a triumph 8" FWH in very good condition with no signs of scoring . A matching pair of sliders will really make the project a goer. Last set of forks i rebuilt were for a 52 TRW found under an olive tree in Northern Cyprus. That was quite a straight forward job but sods law dictates that replacing the oil sealholders on these might involve an awful lot of self control and maybe just a few beers. I don't anticipate a great deal of reconditioning as they were rebuilt by SRM in 91 ( when they were in Penarth.)and haven't had a lot of miles siince then.Steve Macfarland (one of the original SRM partners) is still around and actually rebuilt my TRW engine. i might just give him a ring. Richards Bros in Cardiff rebuilt the wheels for the TRW and i will call them too. Coming together nicely. Knocking off the problems one by one. Thanks to you all for your practical support and encouragement. It really is appreciated.
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Progress on fitting TLS and further.
i have a 8" FWH and a pair of fork sliders with the lug in the right place to slot fully into the TLS plate so what can possibly go wrong! The cable length.
Will get the seals and holders replaced and have asked Steve Mcfarlane (of SRM fame and electric starter kits fame) based here in Cardiff to assemble them and ....... Electric starter?
There's a thought now.
I do like his engineering.skills and his own design electric starter is a superb and elegent solution to "old legs" problem which isn't going away. Unles.....
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I have to say this thread amazes me. Why on earth change an 8" single-sided brake (probably BSA's best stopper) with a FWH whose stopping power is marginal at best? I converted an 8" single sider to TLS and, apart from massive twin discs on my japanese modern, is the best brake I've known. Easily bottoms the front forks.