1965 BSA Front end swap

[BlackCloudSalvage]

Hey y'all. Been a CC member for a few years now, regularly posting in the forums but new to this British category.
Anyhow I picked up a '65 BSA Thunderbolt 650 project that I am going to go through and use for a enduro scrambler. I've been participating in a vintage enduro ride with Speed Deluxe out of Chattanooga for a few years now. First year road a loaner CL350. Then last 2 years road my '75 R90/6. Well I just sold it and picked up the BSA and I'm excited to start getting into it.

Warning: at this point I haven't stripped anything down to take measurements so bare with me. I will get to that point but I'm just wanting to get some brainstorming going and here from those with experience.

I'd like to upgrade the front end with something a bit more suited for the abuse while still staying relatively early and would like to use a drum brake. Also would like to get rid of the stock triple trees with the built in swept back risers. Not sure I like that so much.

I've seen that Betor front ends are a popular upgrade but not sure exactly why. Are they an easy swap?

Also seeing that there are a few vendors that sell neck bearing conversion kits that allow you to run a 71-72 triumph drum brake front end.
I like the stock 19" front wheel and brake that came on my bike and would be happy to use it with the triumph forks but not sure about axle sizes and bore in the brake and hub etc. But would be fine find the matching triumph wheel also.

Lastly I was thinking a XL350 or CL350 Honda front end would be good but not sure about neck stem length and sizes.

Again, just getting some ideas flowing. As I get into it and follow any advice I will certainly engage in the thread and return with measurements etc.

[TriNortchopz]

you know that BSA built an off-road scrambler in the 60's... the BSA Hornet



BSA would sell the Hornet in two main iterations, the Spitfire Hornet of 1964 and 1965, and the Hornet (sans Spitfire) in 1966 and 1967.
https://silodrome.com/bsa-hornet-a65/


Retrospective: BSA A65FS Firebird Scrambler 650cc: 1968-1971:
"Soon the Spitfire Hornet model made its presence known, with no lights and no mufflers, header pipes coming waist high on each side of the engine.
Then that name was split into two models, with the Spitfire being the hot street bike, with a big 5-gallon tank, popular among the race-replica boys, while the Hornet was the off-road scrambler, with a much smaller tank and no street-legal amenities like lights, horn or mufflers."


https://ridermagazine.com/2006/08/20...0cc-1968-1971/


Loud and Free: BSA A65 Lightning Scrambler:


Starting with a fairly uncommon ’72 A65L, they built a 70s-style scrambler with a 750cc big bore kit and a ton of go-fast engine goodies... "
https://www.bikebound.com/2020/01/10...ing-scrambler/

[TriNortchopz]

found this on Britbike forum:

" '70 BSA T"Bolt that I've got. It came with the Ceriani forks in the photo. I removed these & presently the bike has a stock set of forks installed.
I'm no expert on Ceriani, & haven't had these apart, but they appear complete. I believe they are the "MX" type as opposed to the "Road" type (as seen on café racers of the period)."


"I am attaching pictures of several Triumph sleds built by Terry Pratt (RIP) one with Cerianis
and the other with a CZ front end-
he had a beautiful skill that I "borrowed" the look of ......
(and a photo of a couple of "rough customers")

I also have attached an exploded diagram for Ceriani MX fork - don't know if a small .png of it will display clearly"
The dirt track Ceriani's have very little travel so I would recommend the off road versions in Ceriani or Betor.

arly 71 frame, chosen because the oil outlet at the bottom of the frame tube comes out the side instead of the sump plate. It's proven to be a wise choice in that respect.
Betor forks from a Can-Am MX bike,
and at this time, some old stock Girlings shocks.

Front forks are Betor forks with cartridge emulators and stiffer springs. Rear Shocks are Konis, braced swingarm."

https://www.britbike.com/forums/ubbt...50-desert-sled

[TriNortchopz]

Swap out the front end of an old BSA A65
"Member Tune-A-Fish did a BSA Honda fork conversion..".
https://www.dotheton.com/index.php?t...a-a65.77702%2F

[TriNortchopz]

BSA Tapered Neck Bearing Set - SRM

This neck bearing set is made in England by SRM to replace your old steering races and ball bearings

This BSA SRM tapered neck bearing set will fit models including the A50, A65, A7, A10, M20, B31, B33 and others up to approx 1970...

https://www.classicbritishspares.com...-neck-bearings


Taper Roller Steering Bearing Kit, BSA A10/65, Gold Star, Made in UK by SRM
Note; Replaces 65-5126, 65-5127, 66-4149*
https://www.baxtercycle.com/product/srm_tr1/


https://partsbooks.britishonly.com/#BSA650Twin

[farmall]

Honda fork swaps were very common on Britbikes since there were heaps of good used front ends. They're still common which is handy for spare parts.

The tapered roller kit is what everyone sane replaces balls with. You can pick and choose tapered roller outer races and inner race/rollers/cage for a variety of bearings which saves the bearing makers on inventory costs if needed.

Harley 39mm forks look right (the alloy clamps and plain sliders were chosen to mimic Cherry Annie) and offer any tube length plus long travel dampers (TrackerDie or the shorter FXRT stock damper length) so you could run those with an older drum brake if ya don't mind making a mount tab.

Being a racer one might machine an existing disc brake 39mm slider caliper mount into a brake drum stay, or weld up and mill any stock 39mm slider. They look period correct as I've seen a Commando road racer pic with a 39mm HD disc setup.

[BlackCloudSalvage]

[QUOTE=TriNortchopz;859669]'70 BSA T"Bolt that I've got. It came with the Ceriani forks in the photo. I removed these & presently the bike has a stock set of forks installed.
I'm no expert on Ceriani, & haven't had these apart, but they appear complete. I believe they are the "MX" type as opposed to the "Road" type (as seen on café racers of the period).


TriNortchops..... would you want to sell that front end that you removed?

[TriNortchopz]

not mine, found that info in the link I posted at the bottom of the post, this one:
https://www.britbike.com/forums/ubbt...50-desert-sled

[GaryE]

Got to say those images of the Hornet are not very accurate, nor is the associated writeup.

I have both models of the Hornet, the east coast model and the west coast model, as well as the very rare little brother to the Hornets, the 500 Wasp. All are restored back to original factory specs. Currently restoring a '65 Spitfire Hornet and a '65 Cyclone Competition machine, both to original factory specs.

[TriNortchopz]

Beauty collection and very nice restorations.

I found the Roy Bacon books for BSA restorations to be good references:
"The BSA Twin Restoration Book is seen as "The essential guide to the renovation, restoration and development history of all post-war BSA Twins..."

https://www.britishbikebits.com/bsa-...k-by-roy-bacon

[GaryE]

Thanks for the cudo's.

I find that Roy Bacon's books have a lot of misinformation in them. He wasn't much of a bike guy. He just researched and wrote books.