Best 150-350cc fuel injected engine for small, light, aerodynamic reverse trike

[American Viking]

Originally Posted by P-hack

I'd have a hard time chopping up a cb250r, but no problem with an old $300ish bike. Consider one with a title to make it easier to get a plate.

CBR250's get crashed as often as 600cc bikes and written off just as quickly with little to no damage to the frame, engine or driveline. That plastic is terribly expensive.
Call your local bike salvage yard and talk to them about buying a running total of a cbr250, ninja 300. I bet its a lot cheaper than trying to find some running complete bike with EFI.

[user removed]

The Ninja sucks (mileagewise) compared to the CBR, I have owned both, sold both. I like my $650 04 GZ250 which gets mileage better than the Ninja and it's simplicity defined.
I also like the TU 250X Suzuki (owned one of those). Air cooled, EFI,02 sensor (Ninja does not have one Federal version).

regards
Mech

[jkv357]

Originally Posted by Old Mechanic

The Ninja sucks (mileagewise) compared to the CBR, I have owned both, sold both. I like my $650 04 GZ250 which gets mileage better than the Ninja and it's simplicity defined.
I also like the TU 250X Suzuki (owned one of those). Air cooled, EFI,02 sensor (Ninja does not have one Federal version).

regards
Mech

Agreed - but it's amazing how good of numbers they can do with some aero help or careful riding in the right conditions.

If I was going to the trouble and expense of building an aero mpg cruiser I'd skip the Ninja and go for a CBR as a base. I also agree about finding a crashed one to use. It would take a bit more effort, but they are out there if you know where to look.

[user removed]

Salvage HONDA CBR250 for sale

Here are some. In Va they can be titled, salvage titled, or non repairable. I'm not sure how you would get a bike built from a non repairable. Maybe if you built the frame and just used the rest of the parts from the bike.

A salvage title should be fine but you need to check with your state laws as well asthe lawswhere the bike is located.

regards
Mech

[American Viking]

Originally Posted by Old Mechanic

The Ninja sucks (mileagewise) compared to the CBR, I have owned both, sold both. I like my $650 04 GZ250 which gets mileage better than the Ninja and it's simplicity defined.
I also like the TU 250X Suzuki (owned one of those). Air cooled, EFI,02 sensor (Ninja does not have one Federal version).

regards
Mech

Well here in the US market the Ninja 250 was always a carb bike (even the new 300 is carbed here.), so you'd have to convert it to EFI to get the mileage out of it. Second its a twin, so its going to be less efficient but more powerful than a single (the GZ250 is a single). The 2011-on cbr250 single has always been EFI, so of course right from the start it's going to be better than the baby ninja.

Now as far as simplicity the GZ rear suspension is prehistoric. Dual shocks without progressive linkage and a drum brake, yeah that's going to be great fun trying upgrade that system to ride nice with two people on board, never mind stop worth a hoot from 60mph...
Add in that your going to have to do a ton of work routing enough cooling air to the GZ250, as opposed to the water cooled ninja and cbr where you just have to mount a radiator near the front of the vehicle.

Building a reverse trike from a GZ250 is going to take a lot more work in a lot more areas than starting with the baby ninja or the cbr250r.

If I was going to build a reverse trike, I'd look for a narrow middle capacity motorcycle, like a Suzuki SV650, Honda Deauville or some other 600-700ccc water cooled V-twin.
Another useful configuration would be smallish boxer engined machine.

I'd look for a shaft drive. Shaft drive would be useful for maintenance as I'm sure that no one wants to have to take the rear body off the trike to change out a chain and sprockets every 3rd or 4th oil change.

You'll need a wider rear wheel and tire, to handle the load. The gz250 specs a 66 index tire - maximum load for that tire is 694 lbs, Curb weight of the gz is 330lbs, so minus the front forks its maybe 270, add two average sized passengers and its right up on the tires max load. That's before you add trike frame (with its safety cage), front suspension, front brakes, upgrade the rear brakes, add a larger gas tank, all the bodywork, etc...

it would be way easier to work with a little bit larger bike.

[Frank Lee]

Chain drives need replacement every 3rd or 4th oil change? Who knew!

The bodywork must be removed to change this chain and sprockets? Who knew!

Passenger weight? What passenger?

[ScotD]

Thanks all, lots of good info! I'm still waiting for clarification from the state bureaucracy on requirements to license. They ARE working on it. After some good input on the aerodynamics forum I expect I'll stay with narrow body and front wheels outboard. I'll try to design the body for easy access to do maintenance. The various comments have me leaning toward the cbr250r as donor machine, though I think I'd rather find a smaller, lighter, and therefore (all other things being equal) more fuel efficient choice . . . any thoughts on that?

[user removed]

The Ninja 300 is fuel injected (without any doubt). As I said before I owned one. It does NOT have an oxygen sensor (federal emissions cali might have one), which the CBR 250 has as well as the TU205X. I never mentioned making a wheeler out of the GZ250, just that I own one and at $ 650 with 3300 miles one of the best bike purchases I ever made.

http://www.topspeed.com/motorcycles/...-ar160322.html

Viking, you can check my fuel logs to compare the bikes I have owned, and I know the fuel delivery system on each one.

The OE Metzler tire on the back of my GZ250 is rated for a max of 661 pounds, more than the OP's proposed trike bike and his weight combined, on all 3 wheels.

11 different motorcycles in my current fuel log on this site.

regards
Mech

[Grant-53]

There may be some dirt bikes that also may be suitable donors in the 175cc range if re-geared. Forced air and an alcohol/water mist could help cooling. A cylinder head temp gauge is often used to monitor the engine on racing karts. Allow 1 hp for every 36 lbs of gross vehicle weight. Junkyard parts for windshield wiper and ventilation fan. One advantage of a water cooled engine is the ease of installing a heater core for defrost and passenger heat. Chains and belts last a long time if they are kept clean and adjusted.

[iveyjh]

This might bear a good look.

HONDA VTR250 2003 Pearl Shining Yellow.jpg
Manufacturer Honda
Also called Interceptor 250, MC33
Production 1988-1990, 1997-
Predecessor Honda VT250 Spada
Class Naked bike
Engine 4-Stroke, 4 valves per cylinder, 249 cc 90° V-twin DOHC
Bore / stroke 60 mm × 44 mm (2.36 in × 1.73 in)
Compression ratio 11:1
Power 23.9 kW (32.1 hp) @ 10,500 rpm
Torque 23.5 N·m (17.3 ft·lb) @ 8,500 rpm
Transmission 5-speed, wet multi-plate clutch, chain drive
Suspension 41mm showa telescopic fork (front), direct-link monoshock with preload adjustment (rear)
Brakes Single 296mm disc, 2 piston caliper (front), single 220mm disk, 1 piston caliper (rear)
Rake, trail 25°30', 96 mm (3.8 in)
Wheelbase 1,405 mm (55.3 in)
Dimensions L 2,040 mm (80 in)
W 720 mm (28 in)
H 1,050 mm (41 in)
Seat height 760 mm (30 in)
Weight 141 kg (311 lb) (dry)
Fuel capacity 13 L (2.9 imp gal; 3.4 US gal)
Oil capacity 2.4 L (0.53 imp gal; 0.63 US gal)
Turning radius 2.7 m (8 ft 10 in)