Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board 69 triumph forks in 68 a65 frame?

Hi all, still trying to get TLS on my 68 a65. I realize the internals are different between 68 & 69 but what if I use complete forks from a 69? Can I do this and keep my trees and covers? Or do I need to install the complete Triumph front end? Another question not related to the first would a 67 Triumph forks/front end be a better choice. I have option of a complete 67 or 69 complete set up. Thanks for sharing your experience. Harvey

You will not be able to use the Triumph stanchions AKA fork tubes with the BSA triple trees AKA yokes...specifically the top triple tree, due to the taper in the top of the fork tubes between Triumph and BSA models.

Also, the steering stem and associated steering bearings and races are not interchangeable between the two. The Triumphs use a slightly smaller diameter than the BSA's and different steering stop provisions and then there might also be a stem length difference ( the one thing I've never actually compared between the two).

I haven't seen all of your posts, but it seems like you are in a hurry. Patience Grasshopper as this is something you want to get right on the first attempt and is going to take some looking and asking around. It is relatively easy to achieve depending on what's available and how much you are willing to spend.

The 69/70 BSA shuttle valve stanchions will work with Triumph lowers to allow them to fit a BSA set of yokes. However you must have the shuttle valve compression bump stops in the Triumph lowers.

The OP's question is confusing to me. The question starts about installing a TLS hub but then jumps right into swapping forks. What model A65 do you have and what front hub is currently on the bike? If you have a 8" half hub and you want to switch to a TLS hub then yes, lots of things will need to be switched and as the follow up posts point out none of this is simple. Reason I am confused is because certain 1968 A65s did come with a TLS hub and others with the 8" half hub. If you have the half hub and want to switch to a TLS hub you can keep your yokes and damper rod internals and to get a set of 1968 sliders with the axle clamp bottoms. You can then find a 1968 TLS hub which will mount right on. Or you can throw out a wider net and get any of the 1969-70 TLS hubs and then swap the spindle in it (part # 37-2057) with the 1968 spindle (37-1641) and he wheel will mount to your damper rod type sliders.Also realize that whatever fender you have presently may not play well with different type of fork sliders, as the mounting points and type of stays are likely different, so the fender may also have to be changed. If you are lucky, maybe not.

Thank you Peter, yes I have a half hub now and thought it would be easy to switch to TLS. Wrong! Getting 68 sliders is the simplest solution except very difficult to find. 69-70 Are more plentiful but need forks also. I have a full front end from a 69 Triumph. I read somewhere that a company makes bearings and shims to convert to Triumph front. I have some feelers out now.

John, sent you a PM. Thanks, Harvey

Hi Harvey,
Afaik, they're one-year-only?

'68-on, Meriden supplied TLS (and full-width SLS for the 250's) complete with spindles. Pre-'69, Triumph fork yokes placed the leg centres only 6-1/2" apart, 1/4" less than BSA's 6-3/4"; '69-on, Triumph yokes were changed to place the fork leg centres the same 6-3/4" apart as BSA.

So the 37-1641 spindle is 1/4" shorter than the '69 37-2057 and '70-on 37-3582. So afaik spindle clamps just on '68 BSA TLS (and 250 SLS) sliders are 1/4" closer together between two fork legs.

Also if you swap between pre-'69 and '69-on spindles, be sure to keep the brake plate nut on the spindle - pre-'69 is 20 tpi British Standard Cycle, '69-on are 20 tpi UNEF; at least one internal thread (nut) doesn't fit on the other external (spindle) thread.

For a different reason - the cable abutment position - the '68 TLS brake plate is also one-year-only. "69-70" brake plates are "more plentiful" than '68 but only up to a point - while Triumph continued to fit them to '71-'74 T100 500's, because Triumph did evolution not revolution, the TLS is backward-compatible before '68, and Triumph owners have been fitting the better brake to earlier twins for many years.

Both use twenty 1/4"-o.d. balls top and bottom, so they cannot be significantly different? Does your "full front end from a 69 Triumph" include bearing cups 'n' cones? If not, they're easily available; acquire them, measure them and compare with BSA cups 'n' cones?

Hth.

Regards,

Thank you for all your help on this. I've sourced correct forks. Grasshopper was patient and found what he needed! Harvey

That's good to hear, congrats.