Greetings from the USA,
I personally have all singles, but I have a friend who has suffered an injury to his lower left leg making shifting his 1977 Mk 1 850 LeMans virtually impossible. We were wondering if anyone had ever successfully converted one to right shift using bits from an earlier right shift V twin?
Many thanks,
Mike Peavey
Boston, Massachusetts USA
Hi Mike
I have converted my 1974 850T to right foot shift it was quite straight forward as the pedals are operated by two separate shafts that pass under the gearbox. I had to cut and shut the gear change leaver as it is welded on the shaft but the brake is on a splined end so easy just to swap the lever end to end. My bike now resembles a 750S of the same year. You will need to get the shafts and end plates from an 850T. If you look at a parts list there is a picture of them all. The brake on an 850T is a drum brake operated by a rod, so you will have to come up with a different solution for the left foot brake.
Good luck, let me know if you want photos
You can see the parts here, the shaft carrying the foot brake has a splined end both ends so was easy to just swap the pedal (17) and clamp (23). To swap the gear shift I had to cut off the projecting tag that the fork (5) bolts to and weld it back on upside down at the other end. I shortened the pedals as I rear set the foot pegs, but otherwise it was straight forward. You will need to work out how to swap the hydraulic brake though on a Le Mans but this should be possible with a mechanical linkage.
…and on the frame components you will need parts 46 and 47 described as right block and left block respectively, these are the shaft carrier plates that bolt behind the cast foot rest arms
I hope this helps. 
The difference between my bike and a Le Mans would be the rod from the brake lever to the rear master cylinder, if the ear on cross shaft (21) were cut off and welded on the RH end of the shaft the rod to the rear master cylinder could be attached to that…
I have just reassembled the foot controls, cross shafts and support plates
Brake pedal on left hand side on splined end to rear shaft.
Gear change on front shaft, this one needed the welds to the arm ground off and plate re-welded (this is the plate that connects to the gear selector via the ball jointed rod)
Gear lever shaft sits in cups on the triangular support plates that are bolted behind the foot peg carriers and is spring loaded to reduce end float. Radical home made rear sets. The rider foot peg carrier has been cut off in front of the two frame bolts and a stainless steel bar with the foot peg rubber on was internally threaded and bolted through the rear of the pair of frame bolts. The gear and brake pedals were cut short and bent to suit and drilled and tapped for a bolt for the control rubbers.
Both shafts from the rear, sprayed with silver Hammerite smooth.
Shaft listed on ebay if you are still sorting this
https://www.ebay.co.uk/itm/Moto-Guzzi-850T-gear-change-lever-17-25-11-00-USED/273383287772?hash=item3fa6e9ebdc:g:arYAAOSwzZFbYdUu
All that typing and Mike Peavey of Boston, Massachusetts USA never came back, even just to say thank you 
Unfortunately that is just the way it goes some times.
Thanks for that Chris. It will give me some idea of the way to go when I get to that.
Photo Bucket has now messed around with my photos, if you would like copies please send me your email address by PM (not on the open forum) and I will send them to you.
Regards Chris
PM sent