If you're using an early right shift T140 it should be easy, if using a later left shift motor you'll need to work out something for the rear brake. Possibly a cable operated drum or adapt the later disc brake.
When given the choice between two evils I picked the one I haven't tried before
Yes, I have. I built mine nine years ago. Its basically a 1976 T140V ( but with a Tiger head ) in a 1964 frame. As I operate from a Samsung tablet,I still have problems with the picture pisting caper ( not the sharpest knife in the drawer, me!). My brother in law, who is much better at metal fabrication than me, made up a mirror image set of rear engine plates, and by using a Honda CB450 rear wheel, it was a simple(relatively) solution to the rear brake issue. Having a cush drive at both ends makes things smoother, too. To remove the head in the frame will entail removing the rear inner head studs, but everything is straight forward, really
Here's mine. 76 T140 in 69 Bonneville frame. Pretty straight forward. Took the 5speed shifter parts off the old 4speed and put them in the trans cover of the 76. Had to make some new head steadies, bigger head spigots for earlier pipes....nothing too major. If you have the old frame, just seems right to shift on the right
Wow that really brings back the memories... In about 1982 I made a bike similar to the one pictured above. I simply fabricated the top head steady bracket and welded it to the frame. I had adaptors to fit push-over headers. Probably one of the easiest repowers to do.
if using a later left shift motor you'll need to work out something for the rear brake.
Bear in mind the triple front frame was derived from the twin front frame, and the T160 mounts the brake lever pivot in the rear engine plate and the master cylinder on the rear frame, which isn't otherwise different from the twin's rear frame. While it might not all be bolt-on, I can't see that it should be too difficult?
Or the TR65 and TR7T had a right-foot, rod-operated drum that mounts to a version of the oif twin's disc hub. Again, apart from sourcing the bits outside GB, I can't see that it'll be too difficult to fit it all together?
...hello Stuart, Im assembling one; 79 in a 67 frame; I did a mechanism under the frame but I do not have enough space so the rod to the rear brake acts in reverse way...that s not good...I think a cable would be better; the bike is not finished so still without a test. Is it possible to adapt what you say to a normal drum brake with the spool hub?
---hello Jurbanec, you put: "Took the 5speed shifter parts off the old 4speed and put them in the trans cover of the 76"...is it not the other way around? is not clearly what you are saying.
Is it possible to adapt what you say to a normal drum brake with the spool hub?
Pre-disc rear drum brakes normally went on the drive side because the brake pedal was on that side, because the gearshift was on the timing side. Another advantage of this arrangement is that normal right-hand threads in the wheel will tend to tighten in use.
However, Triumph and BSA planned to use the conical hub rear brake in the Bandit and Fury, which had the 'drive-side' on the right - afaict because the standard gearbox had essentially been turned upside-down to give a left-foot shift. Whether this would've meant that the rear conical hub would've dismantled itself in use, and/or BSA/Triumph intended a version of the comical with left-hand threads, we'll never know.
Sorry, just read that - didn't make much sense! In order to make it back into a right shift several of the parts from the 5 speed trans cover need to be put into the old 4 speed cover (if that's what you have). If I remember, that included the kick starter quadrant, the gearchange quadrant, springs, and GC quadrant plungers. Very important not to use the 4 speed plungers...tried that, didn't work. I installed a freeze plug into each side of the cases where the later foot change spindle passed through. Then tapped the primary case hole for an inspection plug to thread into. Really all pretty easy.
...so I need to buy a 4 speed gbox internal cover? you say if that what I have; I have a 79 motor...
It's been a while for me too but I think you only need change the outer cover and gear lever shaft. Swap the quadrant onto that shaft. (Someone correct me if I'm wrong) It would be a good time to renew the two springs inside the outer cover as they weaken with age and are often affected with rust from condensation.
A simple cork would do to plug the hole for the LH shift. I had corks in my engine which lasted for years. Probably still there...