Most motorcycles don’t have a reverse gear, unless you consider the Fred Flintstone reverse of putting your feet down and pushing. In an enclosed trike, that is not possible. How you resolve this is something I would prefer to decide early on before getting the doner bike. You basically have three choices: Use a motorcycle with a stock reverse gear, buy an after market reverse gear, or design and build your own.
Motorcycle with a stock reverse gear
There are very few motorcycles that come with a reverse gear. In fact I currently only know of three major manufacturer motorcycles with a reverse gear, the Honda GL series starting with the older discontinued GL1500 and the current GL1800 and the BMW K1200LT. These are shaft drive and use the electric starter motor to power a reverse gear in the transmission that must be engaged first. The Can Am Spider a stock non-leaning reverse trike has a stock reverse gear with a belt drive. A fourth motorcycle manufacturer is the Russian Irbit Motorcycle Works (IMZ) who produces the Ural which is a heavy sidecar motorcycle equipped with a four-stroke, air-cooled, flat-twin engine, a four speed gear box with reverse gear and shaft drive.
After market reverse gear for trike motorcycles
Below are links to several after market reverse gears for motorcycles, trikes, or motorcycle powered cars.
- Roadstercycle Reverse Gearbox for Trike Motorcycles
- Quaife Reversing Box
- Nova Racing Transmissions in prop reverse gearbox
- eGlideGoodies Reverse Gear Kits for Harley Davidson motorcycles
- Baker Drivetrain Reverse Gear Kits for Harley Davidson motorcycles
Non Gearbox Reverse Options
On the internet I have found ingenious solutions to getting motorcycle powered cars and trikes a reverse gear using automotive starter motors engaging a gear connected to the drive shaft or drive chain. This will require a stout 12 volt electrical system and usage could quickly drain your battery. But you have this same problem the the Honda and BMW motorcycles stock reverse gears as well
Hydrostatic Transmission
Another idea less explored would be to use a Hydrostatic Transmission. Using a bike engine with a dry clutch like a BMW or Moto Guzzi you could replace the gearbox with a variable ratio hydraulic pump and on the driveshaft at the swingarm base put a hydraulic motor. This would also work for a belt or chain rear drive by putting a pulley or sprocket on the hydraulic motor. This would have a lot of advantages like allowing more freedom in engine placement with out worry of how to get the power to the rear wheel. A Hydrostatic Transmission gives you a smooth transition from stopped to full speed without coming off the power-band, by just pushing a lever forward to go forward and faster or pulling the leaver back to slow or reverse. There is a slight loss of efficiency with hydraulics over a direct drive 80% vs. 95%, but it may well be worth it. KTM and Yamaha have experimented with 2 wheel drive motorcycles by mounting a Hydraulic pump at the drive sprocket and running flexible hydraulic lines to a Hydraulic motor on the front forks with a gear driving the front wheel. The motors are surprisingly small and powerful. For a non leaning reverse trike this would be a good solution for front wheel drive by putting hydraulic motors on each wheel