dain
Junior Member
Posts: 63
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Post by dain on Nov 4, 2015 15:29:35 GMT -5
I'm working on a design for single seat gasoline powered light trike. The idea behind it is a person can commute to work with it, achieve 70mph and 70mpg. I will likely seat the occupant closer to the front than pictured to shift my CG as far forward as possible since my engine will be in the pack. The total vehicle weight will come in likely just over 400lbs. Right now I'm looking at the Predator 22hp v-Twin (Honda GX670 copy) with a CVT coupled to a small FNR gearbox and a #40 chain to the rear tire for final drive. I will attempt to make it as aerodynamically slippery as possible which will be the key to hitting my top speed and economy goals... which will probably include some sort of fighter jet looking canopy. I posted my last vehicle build in the "high mileage/efficient trike" section of the forum, It is a 2 seat electric. Chassis isn't completed yet, these are just rough models to determine layout/component placement. If I can't get my CG forward enough I could always make that nose wing out of 1/4" steel plate
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Post by Liteway on Nov 4, 2015 16:55:22 GMT -5
Love your concept, but I think you are far to conservative on the fuel economy estimates. The trike below will achieve 63mpg at a steady 60mph. It has over 4 times the hp you are talking about and weighs about a 150lbs more. Can't prove it, but were its engine fared in and the cokpit closed up in a reasonably slick fashion I think it could achieve your 70mpg goal. The engine is a carbureted 600cc four from the 90s, not likely designed with gas mileage in mind. What you are proposing should easily do 100mpg or better. JMO but 22 hp is a little marginal for highway use. With 15 more from a late model fuel injected 300cc bike, you would have greater fuel economy than what you proposed and performance that would exceed most production cars,assuming you meet the weight target. Regardless, I admire your quest for maximum efficiency and eagerly await the results.
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dain
Junior Member
Posts: 63
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Post by dain on Nov 4, 2015 18:22:10 GMT -5
I agree with your comments, especially the extra horsepower for high speed..
The only reason Im not using a bike engine is it would be difficult to source one if I ever wanted to mass produce.
Cfmoto makes a 500cc engine with a CVT that would be almost perfect, its about 40hp, liquid cooled, and possibly efi. If I find one cheap enough in the next few weeks I may go that route.
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Post by DaveJ98092 on Nov 5, 2015 0:31:22 GMT -5
Dain, Do not over look the big scooters for a trike power source. Honda Silverwing 600, Suzuki Burgman 400 and 650, Yamaha Majesty 400 and a few others. I have three Burgman 650's, two are heavily body damaged and I have plans to trike one soon. I have been commuting 82 miles round trip on a Burgman 650 since 2006. All the above use the "Rubber Belt" CVT transmission except the Burgman 650, it has a special Kevlar belt and the computer controls the CVT with no sliders or clutch packs.
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dain
Junior Member
Posts: 63
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Post by dain on Nov 5, 2015 10:12:06 GMT -5
It's funny you mention that - just last night on eBay I happened across a 500cc engine from a piaggio scooter that I think would work perfectly! Has about 40hp, CVT, EFI!!!, and my favorite part is that it would be sustainable in a production environment as well. If I buy 5 the price comes down to only $500/piece. I also inquired if there is another version available that has reverse gear.. I think I have found my engine!
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Post by Liteway on Nov 5, 2015 10:39:23 GMT -5
I agree with your comments, especially the extra horsepower for high speed.. The only reason Im not using a bike engine is it would be difficult to source one if I ever wanted to mass produce. Cfmoto makes a 500cc engine with a CVT that would be almost perfect, its about 40hp, liquid cooled, and possibly efi. If I find one cheap enough in the next few weeks I may go that route. You really got me thinking about this fuel economy angle. Your point about sourcing bike engines is right. It can be hard to find one you have faith in without buying a whole running bike. Nonetheless, It has raised my curiosity about which bike motors provide the most thrust with least thirst. Going over some figures at fuelety.com has provided some insight. The Honda CBR500R would appeal to me with about 43 rear wheel hp and avg fuel consumption of 65.7 To give an Idea how comparatively efficient that is, a Kawasaki 300 Ninja with 35 rwhp gave but 55mpg. To give me some prospective, I noted the YZF600R motor in my trike gives about 88 rwhp and reported avg mileage was 45.6 as installed in the bike. I average about 53 overall. So, doing some questionable extrapolation: If the bike motor gets 15% better mileage in my trike than in the original bike, applying that improvement to the 65.7 figure of the CBR 500 would net me an average figure of 75.5 A lot of conjecture there, without a lot variables accounted for, but not unreasonable.
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Post by Liteway on Nov 5, 2015 11:08:49 GMT -5
It's funny you mention that - just last night on eBay I happened across a 500cc engine from a piaggio scooter that I think would work perfectly! Has about 40hp, CVT, EFI!!!, and my favorite part is that it would be sustainable in a production environment as well. If I buy 5 the price comes down to only $500/piece. I also inquired if there is another version available that has reverse gear.. I think I have found my engine! Sounds like a practical choice, especially if one is readily available. Not near as efficient as the CBR 500 motor however. MP3 500 owners report 53.2 mpg vs 65.7 at fuelety with about 10hp less at the rear wheel. Guess that's a moot point if you can't source that engine. Anyway, a cvt motor would be an easier installation without clutch or shifter to worry .
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dain
Junior Member
Posts: 63
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Post by dain on Nov 5, 2015 12:08:22 GMT -5
I think there is quite a bit of different info out there about fuel economy on the 500cc Piaggio engine - but I'm guessing the 53.2 you are looking at is close. by nature, a motorcycle like that has a terrible aerodynamic coefficient (likely north of 1.0). With the right design a trike could get down under .3 pretty easily, so that economy number may go way up. I would expect the CBR500 to do better since it isn't losing anything through a CVT belt AND is likely a dry sump motor.
I think it will definitely be interesting to see what happens! A CBR500 would have to be shifted as well. There are a few Chinese motorcycle engines out there that are decent looking but I think the Piaggio motor is definitely a good starting point!
Getting a whole running bike is definitely the way to go if you are using a bike engine IMO - then you get all of the little extra pieces that nobody thinks of!
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Post by DaveJ98092 on Nov 5, 2015 13:47:52 GMT -5
If you can find a clean titled bike that is a huge plus but a salvaged title will work but expect a lot more paperwork and inspections.
On getting a reverse gear, I will build a swinging bracket that will hold an electric motor with a wide gear on it. When I need to back up, pull a lever, the swing bracket will apply the gear to the back tire and hit the electric button.
My Burgman 650 has a CVT but I can put it in manual mode and have 6 shift points with 6th being OverDrive. It also has a "POWER" button that just raises the RPM level for more low end power, nice for down hill twistys. I have 54 Horsepower and average 52 MPG at 70 MPH (best of 58 MPG once) with a touring top case and BIG Givi windscreen. It is full fairing-ed but is as aerodynamic as a barn door, very poor designed radiator opening. I also run a 165/65 HR 14 car tire on the rear so yes for a trike there are car tires that fit.
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dain
Junior Member
Posts: 63
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Post by dain on Nov 5, 2015 14:13:44 GMT -5
That's very interesting that you have a selectable shift mode. Inspections aren't as much of a hassle as you might thing, especially in Iowa. I put my electric trike through a full DOT inspection, took about 15 minutes - stamped a VIN on the frame - put a sticker on it - good to go, same as any other "custom built motorcycle".
I found a 2009 burgman 650 that is salvage title on copart that is close to me, if it ran though it would say so - so that one is a no go.
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Post by DaveJ98092 on Nov 5, 2015 18:51:29 GMT -5
On Copart there are three Burgman 650's with one being in Texas. If they show the Odometer reading most times they run. My first crashed 2008 was DEAD and the dash would light up but no mileage would display. My second 2008 that I crashed this last April runs and just needs the plastics and its a rider again.
Just stay away from 2003 and 2004 Burgman 650s as the CVT has a bad designed input gear and they are loud and have a high failure rate around 50,000 miles. There is a fix for the 2003-04 but it is $225 for a new gear. If the CVT does fail its about $2000 for a new one.
What ever bike you buy, you can sell the un-needed plastics and other parts for about what you paid for the whole bike.
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dain
Junior Member
Posts: 63
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Post by dain on Nov 6, 2015 9:01:45 GMT -5
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