The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: Von datoh on 25.09. 2021 16:37
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Hello, after some advice for my plunger build,I have a conical hub front wheel(71/72 ish) that I want to use,I have standard a10 yokes what is my best direction,I was considering using the conical hub complete forks,does anyone know if they'll fit in the a10 yokes,also are the forks the same length.Its a complete basket case project,that will be a mild custom using period bsa parts before I get told "that's not original",thanks in advance.
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G'day Von datoh, *welcome*
I think you'd be better off using the later yokes as well. I'm not 100% sure they will fit without some modification either. I think the later A65 yokes and forks are wider. What year is your plunger?
Now get over to Introductions and give us your story https://www.a7a10.net/forum/index.php?board=13.0
Cheers
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Hmmm I've just shot blasted the yokes and painted them! :))),You must excuse my lack of knowledge of Brit iron this is my first.I believe the frame is 49,
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G'day again.
"49 should be a long stroke A7, the forks/yokes are same.
Use the "search" for A65 forks.
Cheers
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Search posts under "Yes, No, Maybe." This featured a recent ebay listed special, an A10 frame using the later A65 OIF front end with a conical hub.
So, grafting A65 yokes to a S/A frame can be done. Plunger yokes also differ from S/A type as regards the turn stop arrangement, so plenty of research needs to be done regarding compatability to avoid expensive mistakes.
It is always better to accumulate the bits before making a piecemeal start, then a rough build making sure brackets and such are as required rather than having expensive finishes ruined by the need to tweak, amend or add some insignificant looking but important mounting.
Additional note. Standard pistons won't fit a rebored barrel unless you have already gone down the expensive liner route to take it back to standard bore.
Swarfy.
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Ref barrels they already had new liners fitted and were bored to fit standard pistons,when I acquired them.Are the a65 forks a different diameter to the a10 ones? Was wondering if they could be fitted in the a10 yokes, alternatively I could just find some a10 forks and build them up and fit this conical hub wheel into those I guess perhaps with a modified brake stay?
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All the Fork Stanchions share the same basic tube size across the ranges fitted with the "heavyweight forks" A,B,M and some C models. So interchange between A10 and A65 yokes is possible,
Fork bushes and seals are common across the range. The Fork Tubes vary, in length according to model and wheel rim size, and also the number and size of the holes for the damping action. Later forks have shuttle valve damping, and on the very late conical hub type use fork ends running directly in the sliders. Steel fork sliders share the same internal dimensions for bushes and thread for the oilseal holders, but vary widely as regards mudguard and stay mountings, brake backplate lug arrangement and wheel spindle mounting. Alloy fork sliders are in a world of their own as regards almost everything.
Keeping the Conical Hub probably means a OIF front end complete.
Whatever way you decide to go it will carry a risk when stuff is bought that won't fit. Needs a good bit of further research to get it right with a mix'n match. From a safety critical aspect it is important that components chosen are up to the job.
Swarfy.
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Very useful info there sawrfy,many thanks, typically a complete set of conical forks just went on the bay for just over £100!, nevermind.so do we know which conical forks are closest in length to a10 ones,as I imagine that will change handling,also when you say the conical fork sliders are a world of there own did you mean ref there own mudguard mounts etc,as I'm not to fussed on strict original (although prefer the look of a10 forks,not the price!:)as long as it's bsa "period"many thanks again.
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Forks for the Conical Hub are a completely different design, the so called "upside down" type. View a few images of bikes from 1970's and you'll see the major differences. Draganfly have an excellent online parts catalogue which is a very useful resource.
Swarfy
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Yes I will do that's a good source of information,next job is getting the front end parts together(after I've built the rear end!)anybody none the wiser on the stanchion length or have a link to thread ref a10/a65 length *smile*
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OIF forks are Ceriani-based and work well, but I don't think they (or the conical hub wheel) look good on earlier bikes. Only my opinion though. ;)
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Fair opinion,I got the wheel complete for a good price,I do prefer the "look" of the earlier forks just depends what comes up at a sensible price.I didn't want to build a 100% original bike,that's why I bought loads of spares to build up a "period correct" mild custom so I can get it registered as a classic. *smile*
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Hello,if you decide not to use this front end i would be interested as i am changing the front end on my plunger