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BSA A65 DISC FRONT END? #276100
09/24/09 2:38 am
09/24/09 2:38 am
Joined: Sep 2009
Posts: 21
New York, USA
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BloodySoreA55 Offline OP
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BloodySoreA55  Offline OP
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Posts: 21
New York, USA
I have a 1967 A65T that has the triple tree but thats it in terms of a front end. I would like to convert the front end to a disc brake and i was wondering if it would be possible to do so cost effectively I.E. use a jap front forks wheel disc brake etc. Has anyone done this? is there a fork set from a disc brake bike that will mesh with triple tree from the BSA? i would really like to avoid chopping the frame as i cant weld and dont really have the money to pay someone else to do it. thanks in advance

1948 BSA C10
1970 BSA A65T
1967 BSA A65T (in progress)


DCF

1948 BSA C10/11
1970 BSA A65T
1967 BSA A65T project
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Re: BSA A65 DISC FRONT END? [Re: BloodySoreA55] #276113
09/24/09 6:05 am
09/24/09 6:05 am
Joined: Jan 2004
Posts: 3,700
ca, us
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DMadigan Offline
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ca, us
Cheapest to obtain would be a Japanese fork, cheapest to fit is probably the T140 disc front end. I believe someone has a taper bearing retrofit so the stem diameter would work. Length is another issue but I believe the OIF headstock length should be close. Most UDFs have a larger stem diameter than your A65. An earlier Japanese front end would have a smaller diameter stem but the quality of the forks might be lacking.
Why not use a comical hub twin leading shoe from '71-'74?

Re: BSA A65 DISC FRONT END? [Re: DMadigan] #276127
09/24/09 10:05 am
09/24/09 10:05 am
Joined: May 2004
Posts: 3,728
Sydney Australia
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BSA_WM20 Offline
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Sydney Australia
My ex flattie had a dry frame A65 with a T140 disc and it handled like a sack full of wet spuds at anything under 50 mph .
Even worse was the fact that My OIF A65 fitted with properly set up comicals out braked it hands down


Bike Beesa
Trevor
Re: BSA A65 DISC FRONT END? [Re: BSA_WM20] #276135
09/24/09 11:33 am
09/24/09 11:33 am
Joined: Apr 2005
Posts: 2,380
Bega NSW Australia
Mark Parker Offline
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Mark Parker  Offline
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Bega NSW Australia
You can fit older or newer for that matter Jap front ends, this has a Yamaha 650 or 500 front end in machined BSA trees or you could modify and fit a different tree. No need to weld frame though this one is altered in other ways.



mark
Re: BSA A65 DISC FRONT END? [Re: BloodySoreA55] #276156
09/24/09 1:57 pm
09/24/09 1:57 pm
Joined: Sep 2009
Posts: 21
New York, USA
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BloodySoreA55 Offline OP
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BloodySoreA55  Offline OP
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New York, USA
Im thinking it might just be easier to find a set of a65 forks that will definately fit and then put a wheel with disc brake on. thanks for all the help guys.


DCF

1948 BSA C10/11
1970 BSA A65T
1967 BSA A65T project
Re: BSA A65 DISC FRONT END? [Re: BloodySoreA55] #276174
09/24/09 4:07 pm
09/24/09 4:07 pm
Joined: Jun 2002
Posts: 9,879
Scotland
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Stuart Offline
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Stuart  Offline
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Hi,

Originally Posted By: BloodySoreA55
Im thinking it might just be easier to find a set of a65 forks that will definately fit and then put a wheel with disc brake on.

I doubt it (although I'd be happy to be corrected).

1. Fwiw, I've fitted a Triumph disc-brake front end to a '69 T100. If the A65 headstock is the same as the contemporary Triumph, you use '73/'74 T150 yokes (triple trees), 'cos the stem's the right length and the cup-'n'-cone bearings match. However, I'd advise against using a complete T150 front end, 'cos the triple's 100lbs heavier than a twin; my T100 has disc-brake twin fork internals.

2. Your idea of using A65 forks in the yokes you've got is possibly not a bad one in theory - the factory '71 triple racers used pre-'71 forks with caliper mounts welded to the sliders. However, I'll take an educated guess that the yokes were wider than 1967's standard 6-1/2" between stanchion centres, and you'll need to find someone who can weld those caliper mounts very, very well. Dave will doubtless come back with corrections and more information as he knows much more than I do of those racers' details.

3. In theory it might be easier to fit Jap disc-brake sliders to A65 stanchions in your existing yokes, because Jap calipers are usually single-sided so the stanchions can be closer together. However, I can help thinking you are going to be very, very lucky to find parts made decades and continents apart that can be joined together without a very great deal of work.

At the end of the day, you sure you wouldn't be better off with standard '67-'69 forks and a '68-'70 tls drum brake? wink

Hth.

Regards,

Re: BSA A65 DISC FRONT END? [Re: Stuart] #276178
09/24/09 4:36 pm
09/24/09 4:36 pm
Joined: Dec 2002
Posts: 406
Chelmsford MA
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MarcB Offline
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Chelmsford MA
A member of the group named Redman has dual-disc front-end on Buster:



Maybe he can help you.

Re: BSA A65 DISC FRONT END? [Re: MarcB] #276191
09/24/09 5:33 pm
09/24/09 5:33 pm
Joined: May 2005
Posts: 3,814
ohio
shel Offline
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shel  Offline
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ohio
I seem to remember Redman saying the front end came off a mid nineties 600 Honda but I could be wrong.


When given the choice between two evils I picked the one I haven't tried before
Re: BSA A65 DISC FRONT END? [Re: shel] #276195
09/24/09 5:50 pm
09/24/09 5:50 pm
Joined: Jun 2008
Posts: 197
portland, oregon, USA
Paul Burdette Offline
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Paul Burdette  Offline
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Posts: 197
portland, oregon, USA
if it helps, several '70s honda CBs (500, 550, 750) have 35mm forks. i've seen them mounted to OIF bikes for a disk front end, but i don't know the diameter of your stanchions. the models listed above also ave mirrored forks, so you can use two disks.

i think it'd look funny on an otherwise stock bike, but would probably blend in fine on a race or cafe racer bike.

Last edited by Paul Burdette; 09/24/09 5:50 pm.

1972 Norton Commando Combat
Re: BSA A65 DISC FRONT END? [Re: BloodySoreA55] #276201
09/24/09 6:19 pm
09/24/09 6:19 pm
Joined: Sep 2009
Posts: 21
New York, USA
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BloodySoreA55 Offline OP
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BloodySoreA55  Offline OP
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New York, USA
I agree in that it would likely look funny but my bike will be far from stock looking i can assure you. I have a complete engine that im nurturing to life and a very rough frame thats completely bare aside from the swingarm and triple tree. Im in college and live on my own so my budget is extremely small. I am trying to craft myself a daily rider. Hence, i was wondering if it would be more cost effective by going with a jap front end with a disc. I know getting stock bsa parts can run a pretty penny. Essentially what im looking at is getting the most bang for my buck. Not trying to build a racer (stock thuderbolt engine)just a bsa that i can improve while getting it back to the roadway. I do have a nice chunk of spares from previous a65 resto (where the triple tree came from) but i am still lacking a front end. If i did get a jap front end youre right in that it may not mesh without modification which may in the end cost more than just getting a stock front. So i guess ill just keep my eyes peeled for either. thanks for all the input guys


DCF

1948 BSA C10/11
1970 BSA A65T
1967 BSA A65T project
Re: BSA A65 DISC FRONT END? [Re: BloodySoreA55] #276240
09/24/09 9:58 pm
09/24/09 9:58 pm
Joined: Nov 2007
Posts: 71
orofino Idaho
Mike, in Idaho Offline
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Mike, in Idaho  Offline
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orofino Idaho
I used a honda CB500 front end on a T100,, used the whole thing since the triple trees are wider. In My case the steering stem length was almost the same so all I needed to do was turn out some bushings for the steering races and grind a bit off the steering stops to get things to fit. Early Honda fours use 19 inch 40 spoke front wheels, just like a proper motorcycle.


Mike

My company car is a Kenworth
Re: BSA A65 DISC FRONT END? [Re: Mike, in Idaho] #276267
09/25/09 3:09 am
09/25/09 3:09 am
Joined: Oct 2008
Posts: 5,000
Gnashville
DavidP Offline

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DavidP  Offline

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Gnashville
I have a Triumph disc front end on my 71, but I bought it that way. Don't know how much trouble it was to mount.
They did use a Honda master cylinder, though.

Mike's 500 looks like a winner. You can probably locate a similar front end more easily, and for a whole lot less cash, than trying to find a good T140 set.


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
72 T120V cafe project "Mr. Jim"
Re: BSA A65 DISC FRONT END? [Re: DavidP] #276346
09/25/09 7:29 pm
09/25/09 7:29 pm
Joined: Feb 2002
Posts: 484
Stafford, UK
Andy Lorenz Offline
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Andy Lorenz  Offline
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Posts: 484
Stafford, UK
I got a Kawasaki Gpz wheel and forks into my A65.
I used the standard BSA bottom yokes, and mage a custom top yoke because the kawasaki needed clamps, not tapers at the top.
The wheel fitted, but I had to loose the front wheel speedo drive since the A65 yokes are narrower than the kawasaki.
I also made up some front headlight shrouds so that it looked BSA'ish.


Thrash, Bang, Re-Build...
Re: BSA A65 DISC FRONT END? [Re: Andy Lorenz] #276407
09/26/09 4:51 am
09/26/09 4:51 am
Joined: Aug 2006
Posts: 680
S.W. Pa.
breeze1954 Online content
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I believe a complete Honda sohc 750 is the easiest (but not the best) jap frontend I have found to put on a pre.71 A65. You buy or make a set of bearings race cups for the neck and sheíll mount right up. They lengthen the neck to match the stem and jap bearings. You will need to mod some stops though. Some of the aftermarket companies used to sell the cups, I think Domi was one but donít remember for sure, that was in the 70s and 80s. I think I still have an old set hanging above my work bench, Iíll have a look, if they are still there Iíll check for a name or part # on them. Iíll also take a picture of them and post it up if it would help, so you will know what a set looks like. Then you can do some swapmeets, never know, you may find a set and a frontend on the cheap to boot.

I just love customs made for riding!
beerchug


Nothing ticks you off more than that moment during an argument when you realize you're wrong!

Ride Safe When You Can; Tim

Small print Disclaimer: I am not responsible for spelling, grammar or political correctness. Actually IĎm not very responsible at all!
Re: BSA A65 DISC FRONT END? [Re: BloodySoreA55] #276416
09/26/09 9:39 am
09/26/09 9:39 am
Joined: Jul 2009
Posts: 3,549
Vic. Australia
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Pete R - R.I.P. Offline
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If you fit an early honda 750 front-end,use the internal springs from a pre-unit Triumph (beautiful roadholding).These springs will probably fit a lot of other Jap front-ends,if they were fitted on a bike that's too heavy or too light.

Re: BSA A65 DISC FRONT END? [Re: Pete R - R.I.P.] #276439
09/26/09 2:15 pm
09/26/09 2:15 pm
Joined: Aug 2006
Posts: 680
S.W. Pa.
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Thanks for the info Pete, Iíve put a few of those on BSAís and other brits over the years but never figured pre-unit springs working. Those frontends always did need something. Tried the aftermarket progressives and didnít help worth the cost, so Iíll have to try them if and when there is a next time. Goes to show you can always learn new tricks.
beerchug

Last edited by breeze1954; 09/26/09 2:16 pm.

Nothing ticks you off more than that moment during an argument when you realize you're wrong!

Ride Safe When You Can; Tim

Small print Disclaimer: I am not responsible for spelling, grammar or political correctness. Actually IĎm not very responsible at all!
Re: BSA A65 DISC FRONT END? [Re: Pete R - R.I.P.] #276462
09/26/09 7:07 pm
09/26/09 7:07 pm
Joined: Jun 2008
Posts: 197
portland, oregon, USA
Paul Burdette Offline
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Paul Burdette  Offline
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Posts: 197
portland, oregon, USA
Originally Posted By: Pete R
If you fit an early honda 750 front-end,use the internal springs from a pre-unit Triumph (beautiful roadholding).These springs will probably fit a lot of other Jap front-ends,if they were fitted on a bike that's too heavy or too light.


i've had great luck with progressive front springs for the 70's hondas. they still like a little preload in my opinion, but that's easy with some 1" PVC pipe. also, i convert the honda forks with cartridge emulators, available through race tech, or from mike's XS for about a quarter the price. for what it's worth, the 500/550 front end is shorter than the 750, if you want to steepen the steering angle a little. here's my honda front end with dual disks, cartridge emulators, tarrozzi brace, and progressive springs. if i were building a cafe racer out of a triumph or BSA, i'd consider it a decent option.




1972 Norton Commando Combat
Re: BSA A65 DISC FRONT END? [Re: BloodySoreA55] #276848
09/29/09 12:36 pm
09/29/09 12:36 pm
Joined: Aug 2007
Posts: 113
fairport new york
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richard p Offline
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fairport new york
I am in the process of collecting parts to graft a T140 disc brake front end onto a pre-1971 frame. The cost of the actual forks and triple trees was not too bad... but then I needed all the other parts and pieces! I have acquired most everything I need with the exception of a master cylinder and the actual hoses to get the juice to the caliper. I still am researching what my options are without going completely "Triumph". I have made up the necessary bearing cups and spacers needed to use the triumph triple trees.... I believe you can purchase these ready to go.

The other item that you will have to address is the fork stops..... I had to make a custom one on an earlier BSA project (where I grafted on a 1971 conical front end). It would be a shame to damage a gas tank if the forks are free to move too far.

So what I actually have found out.... by learning the hard way (yet one more time) is to do your homework!!!!!! The price of acquiring all the parts was more than I had anticipated when I initially found the front forks. I would have been much better off buying a "complete" front end, wheel master cylinder, handlebars, matching levers etc .... as long as it all was useable! A complete bike (basket case) would have been a better choice....

I am too far into it at this point.... but in hind sight.... I might have considered a sportster front end with dual discs.... but once again... buying something complete that is useable.

I tend to jump into things quicker than I should.... although I think I am getting better.... LOL. I thought I could get away with a triumph disc front end for under $300...... Boy was I wrong....(as luck would have it.... many items turned out to be unuseable... master cylinder wise..... and to replace all that with Triumph parts.... $$$$$

Just my two cents to add..... Good luck with your project hopefully you are luckier than me and find a useable complete front end!!!!

Re: BSA A65 DISC FRONT END? [Re: richard p] #276873
09/29/09 3:50 pm
09/29/09 3:50 pm
Joined: Jun 2002
Posts: 9,879
Scotland
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Stuart Offline
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Stuart  Offline
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Joined: Jun 2002
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Scotland
Hi Richard,

Originally Posted By: richard p
T140 disc brake front end onto a pre-1971 frame.

At the risk of a thread hijack ... without wishing to sound like a smart-arse at all ... you should've asked first ... whistle

Originally Posted By: richard p
I have made up the necessary bearing cups and spacers needed to use the triumph triple trees....

Ime and mho, an oif bottom yoke in a 'dry' frame is too much hard work and expense for the result - the bearings are different (oif taper roller, 'dry' cups-'n'-cones) so either you have to make up or buy loads of little bits and pieces. But that still doesn't make the oif steering stem long enough - you'll only get a few threads in the top nut. frown Otoh, if you use a T150 bottom yoke (top yokes are the same), it's a bolt-on ... bigt

Originally Posted By: richard p
I have acquired most everything I need with the exception of a master cylinder

I used (Sparx pattern) T160/'76-'78 handlebar switch clusters and master cylinder mounting, but with a stainless master cylinder, because that's what I wanted. If you go for Jap switchgear and master cylinder, bear in mind the standard Triumph/Lockheed single-disc master cylinder is 5/8" (16mm) i.d. whereas most Jap ones are 14mm (9/16") i.d.

Originally Posted By: richard p
and the actual hoses to get the juice to the caliper.

I made them out of Goodridge braided hose (plastic-covered) and stainless fittings, because I wanted to incorporate a proper hydraulic brake light switch (as used by Meriden '79-on) instead of relying on that ridiculous pre-'79 Heath Robinson device. mad Only thing to bear in mind is, if you want the hose bracket that attaches to the slider at the mudguard/fender mounting, you can't use normal Goodridge -03 flexible hose from there to a standard Lockheed caliper - the bend radii are too tight. I wanted it to 'look' standard so I had one of Goodridge's 'hard line' customers copy the standard Triumph pipe in stainless but, really, the much cheaper option would be to have one flexible hose from lower yoke to caliper.

And, as always, I use DOT5 brake fluid.

Pm or e-mail me if you'd like some pictures or other details. wink

Hth.

Regards,


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