Thread: 3-wheel daily driver....looking for input

Tweet

I saw my first T-Rex the other day and although I didn't have time to take in all the details of it like I wanted to, it left a lasting impression on me. I'm not interested in going from 0-60 in 4 seconds, but I am interested in a commuter-type vehicle that would haul 2 people and a few bags of groceries while getting 50-60 mpg and still be tagged and insured as a motorcycle.

I began looking through motorcycle specs for a good candidate. At first, I was thinking a 4-cylinder, around 1000cc's like some of the Kawasakis, but then after I thought about it, I realized that it would be too much power and it wouldn't get the mileage I envisioned. After a couple of days of looking, I happened upon the Kawasaki KLR650. It's a dual-sport single with dual overhead cams and 4-valves, electric start and it's water cooled. Looking through different ads, I found that you could take one home for anywhere between 1500 and 3000 dollars. That's for a low-miles example, with less than 10,000 miles. These bikes are still runnin' great with 20,000 or even 30,000 miles on them, so if you could grab a 4-digit mileage unit, there would be a lot of service left in it.

I thought all different ways for the main cage. A fellow could use square section mild steel like the Locost or you could use thin-wall chromoly tubing or you could fabricate a boxed sheet metal frame section or if you really wanted to get jicky, you could learn how to cast HDPE.

I think the front suspension should be unequal-length upper and lower A-arms using handbuilt spindles mounting two front wheels and tires from a KLR650. A lightweight rack & pinion, ala '72 Pinto could do the steering. Coilovers with the proper spring rate (very light) should work. I have hand-built this type of suspension and if I can do it, anybody can, and make it right. The system I put together had 9 1/2" inches of travel in bump and droop with zero bump steer on a dial indicator. You can learn how to do it by reading "Tune to Win" by Carroll Smith. Then again, there's nothing that says you couldn't run a straight axle. Mount the R&P to the axle and you're in like Flynn.

The thing that I didn't get to see on the T-Rex is the reverser. As you know, there is no reverse on bikes (well, maybe there is on some exotics), so you have to have a way to back the rig up. I was thinking maybe a plastic wheel off a toy with a strip of rubber around it and a small 12v electric motor with a gearset that would allow the wheel to roll maybe 10 rpm's and a handle/pivot arrangement operated manually by the driver. I don't know for sure about this. I haven't done too much thinking on it.

For seats, I was thinkin' patio chairs with mesh. A couple of pounds each. I've seen some nice black ones with an oval steel frame and a close-knit mesh that were very attractive.

You could leave the fuel tank in place or install a larger cell, as long as it was above the carb. You might even leave the seat in place and have room to carry four people.

Some nylon strapping sewn together like a window net on a race car could be fashioned into lightweight luggage or grocery bag carriers.

The T-Rex weighs in at just under 1000 lbs, but I'm thinkin' that with the right choice of plastics and other lightweight components, you could get way under that. I was even looking at some nylon rod ends.

Anyway, I would welcome all contributions from you fellows. A bunch of heads are better than one.
Campagna- Fun, Style, Performance

Been considering a similar project for a couple years Richard... Gained a lot of good ideas looking at front ends off some of the sport and racing quads that are 2 wheel drive, some very neat suspension goodies on them....

Of course, a quad. I was racking my brain trying to come up with a lightweight front end assembly that was already engineered and produced. Never considered a quad. Thanks Dave, will do some research.

The two wheel drive "sport" (aka racing) Yamaha has some really great components on the front end!!! As hard as they are ridden I would imagine they wreck a few of them.... Got a motorcycle junk yard down there to check out???

The larger 600 and 700 cc Kawasaki's and Yamaha's are mostly all 4wd stuff. One I looked at would require nothing more then removing the half shafts and a U-Joint yoke to make it a 2 wd.---think that was a Yamaha Grizzly maybe???

Even the plain Jane quads have a lot of front end travel, some of the race quads look like they have about 7 or 8 inches of travel and are heavy duty enough to take some really serious pounding in the dirt!!!!