RWD reverse trike Design Stage

[HydroJim]

For those who have seen my other threads, I was thinking about chopping a geo metro in half and turning it into a reverse trike. But I figured if I was going to put that kind of work in, I might as well build something from scratch just the way I want it.

So I've decided to build something as a combination between these 2 machines:




It's going to fit 1 person and I'll probably use a Kawasaki 250r as the donor bike because they are cheap and plentiful!

I'm going to probably use this kit
Kawasaki Ninja 250r Fuel Injection Conversion Kit - Small Engine EFI Conversion kit | fuel injection kits
for the engine so that I have complete control over the engine and be able to lean out the engine on the highway.

Biggest challenges are going to be
the front suspension/steering.
Braking system
shifting gears? not sure how this would all work.

If you have any info or help to help me start creating this thing in my mind, please feel free to share.

[Christ]

Shifting gears isn't a concern at all.

Everything you need is already there except a lever. Make a lever that travels forward/backward, place it in the cabin where you want it, call Motion Pro and have them make a cable the way you need it that is capable of push/pull motion, then make the mounting tabs for each end of the cable. Remove the 10mm nut from the transmission shift drum actuator arm (circle that clamps on the splined rod with a tab on it), drill the spherical joint out and bolt the transmission end of the cable on it, then reattach it to the trans.
Attach the other end of the cable to your shifter lever and make sure it functions properly, then add stops so you can't over-shift, which can damage shift forks.

If you don't want to use a cable, just make sure you can line up the lever with the actual shift mechanism within a few degrees and then you can use the original setup with a longer rod. You can actually use the original foot lever with a longer rod and place it next to the seat, too. You just pull the bolt in the center of the rod and pull it off, cut the rod in half and weld in an extension.

Braking system will depend on how you set up the suspension/steering and what type of wheels you use.

If you want to avoid brake drag, you can get both solid spoke and wire-spoke wheels with drum brakes in them, saving you the weight and expense of adding spindles, bearings, hubs, etc.

You can mount car tires on motorcycle rims with no problems, but most of the wire-spoke wheels use tubes, so you would need to get a tube that matches the tire size you intend to run.

If you want to use pre-existing parts for the steering/suspension, consider using a-arms from ATVs or UTVs, or if you'd rather, use the entire hub/steering assembly from any car and build your forward frame section around it (You can even use McPherson parts.)

[Sven7]

I have been planning a similar project off-line. One concern was lack of a reverse gear. Apparently Goldwings had them, or you could rig up a small motor to the axle.

Get the smallest front brakes you can find because it's going to be quite light. Maybe buy a CRX for all the little parts- brakes, gauges, steering rack, suspension? VW Rabbits also have tiny brakes and are not hard to find. They have McPherson struts however, which is worse for handling.

For suspension geometry, read up on some Lotus 7 replica forums. There are suspension calculators that will tell you everything you need to know. I've been considering a Ford-style twin I beam setup that would be very simple and hopefully durable.

What are you thinking about for the actual body? I am planning on custom building a body out of fiberglass, allowing me to design a bespoke (and fully faired, awesome looking) body. Windows will be of lexan or similar.

I don't know how artistic you are but if you'd like help on the styling front give me a holler. And keep the wheels forward or it'll look weird!

An early stage of my model. I've lowered the H point and will probably abandon this package.


Does anyone know the ins and outs of legalizing a custom built vehicle like this? It's obviously not a "replica" so at some point you're going to have to pass an inspection. What would they look for?

[Christ]

The reversing gear is usually just an electric motor either with a separate clutch or with a lever that engages the sprocket into the chain (moves the whole motor/sprocket up and down).

They use that setup on trike conversions often.

[Christ]

Of course, you could almost just shoulder it backward. We're talking about a vehicle that, completed, should have a max weight under 1,000 lb by far.

[Christ]

Originally Posted by Sven7

Does anyone know the ins and outs of legalizing a custom built vehicle like this? It's obviously not a "replica" so at some point you're going to have to pass an inspection. What would they look for?

You're able to register 3 wheeled vehicles in most states as motorcycles. If you're using a motorcycle frame for the main section of the vehicle, you can probably send it for a basic vehicle inspection and just update the title to reflect the modifications (weight, wheel base, number of wheels).

[Sven7]

Originally Posted by Christ

You're able to register 3 wheeled vehicles in most states as motorcycles. If you're using a motorcycle frame for the main section of the vehicle, you can probably send it for a basic vehicle inspection and just update the title to reflect the modifications (weight, wheel base, number of wheels).

Well, the whole point of the question was, what if you're not basing it on an existing vehicle. What if it's a completely hand-built chassis and body.

[BackroadBomber]

I don't know about your state but here in NY you're better off registering it as a motorcycle. Granted, you have to wear a helmet, but you need absolutely no safety gear. I have the packet from the NYSDMV on registering a homemade car and basically they say whatever year the engine is, is what year the car is. So if you use a 1972 engine, you're pretty much free to build anything. If you use a 2011 engine, you need everything a 2011 car needs such as obd-2, air pressure sensors, catalytic converter, safety glass, smog equipment, traction control, etc. but like I said, every state is different so you'd have to check your local DMV

[Frank Lee]

Can't speak for every place but if your trike or even bike has an enclosed cabin, you don't need a helmet.

[Christ]

Originally Posted by Sven7

Well, the whole point of the question was, what if you're not basing it on an existing vehicle. What if it's a completely hand-built chassis and body.

The whole point of the answer was "Build it how you want, but use the neck from a bike."

This gives you the ability to register it as a modified version of the bike from which you stole the VIN.

Honest? Not totally.

Does it work? 60% of the time, every time.

If it doesn't work, they'll just make him fill out a different set of paperwork and wait literally forever and 4 days for a title application form, then fill that out and have it inspected, have the mechanic sign it, go back through the process again to receive a conditional or bonded registration, blah blah blah blah...

Except in Maine. Just get a hobbyist plate and throw it on, apparently.

Anyway, if you're going to use a bike engine on it, just use the neck from a similar bike somewhere in the design, that'll let you use the title from that bike and save you a lot of hassle.