Building a trike...

And when i say trike, i mean a motorised, road version

Any ideas, tips, suggestions etc? Ive googled stuff but there is ALOT of crap out there on the WWW!

I have basic engineering/automotive knowledge, and my mate is a qualified/certified engineer in the heavy automotive industry, so no problems with the actual construction of such a project, but just the need for plans etc...

I think a number use IRS with a real diff out of a ATV. Shaft drive bike and a shaft drive Quad rear half welded onto the frame of a 2 wheeler. go look around a quad bike place and see what has a IRS and diff, then find a rolled quadbike of the same model bike with munted front to scavenge the rear off.

IRS? I want it road legal and able to sustain 100km/h easily and (fuel) effiently, so dont know if a quad diff would quite cut the mustard....?

Independant rear suspension.

As opposed to the Inland Revenue Service Andrea and others fled from in the USA.

Modern quads diffs are pretty capable.

I haven't paid too much attention to road trikes, but of the 4 guys I talked to at a car show once, 2 were running quad IRS systems, and one was running a suzuki feroza (solid) rear end in a fabricated frame and the last had a subaru R160 IRS LSD and a fabricated frame.

Quads rev lower and slower than most road bikes I understand and are tuned for low down torque, while road bike motors are tuned for higher rev power, so a quad rear diff does fairly well.

Guess that makes sense! So any hints/suggestions for sourcing an engine? And any suggestions on a particular model and make?

Hmm... a front end, find a 600cc or better cruiser with shaft drive at a junk yard that got rear ended, chop the rear off just behind the engine under the seat, find a IRS quad post 2001 with a good top speed, most do about 60, by the time you add the faster rev bike engine and larger diameter rear tyres you ought to have 100Km/H capability, cut it's frame off in front of the rear suspensions forward joint and make a frame to join the two bikes.

fromt hen it's all cosmetic

I know a guy making one with a toyota V8 engine, another had an old 250ci falcon engine, VW engines were popular with them for a while.

But the question is WHY???