Selecting A Doner Motorcycle

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Which comes first, choosing a motorcycle to to design your leaning reverse trike around or designing your leaning reverse trike and then find the doner motorcycle that best suites your design? Its a classic chicken or the egg scenario. Unless you already have a motorcycle ready for the operating table, the best answer is to do a little of both. You should at least be settled in your mind about engine placement (fore, mid, or aft), drivetrain (chain or shaft), and how you will implement a reverse gear. Are you building a cruiser or a race car? What is your budget for the motorcycle? These all should have an impact on your motorcycle selection. Once you have figured out the ideal motorcycle for your you leaning reverse trike, it’s time to obtain it and design the details of your leaning reverse trike around it.

My First Choices

Currently I am leaning toward a cruiser with a front mounted engine, drive shaft and a stock reverse gear. I also want reliability and parts availability. This leaves me with three motorcycle model choices:

Honda GL1800

The Honda GL1800 has all the requirements I have for my concept of the leaning reverse trike, but is probably out of my price range. A 2002 GL1800 with 100,000 miles and some major front end damage will go for over $4000.00 at a salvage auction.

Honda GL1500

The Honda GL1500 also has all the requirements I have for my concept of the leaning reverse trike and the price is more reasonable. On the down side it is an older motorcycle no longer produced and tends to have higher mileage and more ware and tare. If I can find one in the last few years of its production run at the right price I will get it.

BMW K1200LT

The BMW K1200LT is an excellent choice, it too meets all my leaning trike concept requirements. The BMW K1200LT is harder to come by, but go for a more reasonable price at salvage auction than the GL1800. I also am vainly thrilled with the simple idea of having a BWM hood emblem on the finished reverse trike.

Other Doner Motorcycle Options

If I just remove the stock reverse gear from my requirements, the list of motorcycles to choose from grows much larger. It now includes most shaft drive motorcycles. Because I want a front mounted engine I will be needing to extend the drive shaft from the engine in the front to the rear swingarm. I can use a aftermarket reverse gearbox inline with the driveshaft. The gearbox will cost an additional $1000.00 – $1600.00. This would give me a very robust reverse gear, but need to do more research to decide if it is cost effective.

If I were to use a rear engine mount, I would no longer want a shaft drive and I could use an after market reverse gear box as a jack shaft on a chain or belt drive. There are also reverse gear kits for Harley Davidson motorcycles. I could use almost any chain driven motorcycle on the market.

Screw It! I’m getting a Suzuki Hayabusa (GSX1300R). Stick a reverse gear and jackshaft on it and I’ll be carving those canyons! Just kidding, well maybe not?

Reversing a Reverse Trike Motorcycle

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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.

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