Motorcycle Experts! I SUMMON THEE!

"ptak appreciates old racecars" (racecarptak) 08/31/2014 at 15:47 • Filed to: two wheels bad

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Rise from the depths!

So I'm undertaking a little project, I guess you could call it a go-kart of sorts, except it's larger. My idea is to build a small car in the style of a Bugatti Type 35/1920s racecar, only instead a single-seater, and slightly longer than an Austin Mini. I envision the thing to weigh between 300 and 400 pounds.

I've gone through a bunch of car engines measurable in the ccs, but nothing fits. I surmise my only decent option is a bike engine. Long story short: are there any motorcycle engines which I can use, which are fairly reliable/durable, and which aren't too fast or powerful (I don't want to kill myself)?

Your help is greatly appreciated! :)

RWS Motorsport > ptak appreciates old racecars 08/31/2014 at 15:53

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I have literally no knowledge of motorcycles beyond that they have 2 wheels too few, but the Formula Student team at my uni used a Yamaha R6 engine. quite powerful, small, 600cc (i think?) and should be fairly reliable. The uni had used the same basic engine/block for like 6 or 7 years i think.

Jeff-God-of-Biscuits > ptak appreciates old racecars 08/31/2014 at 15:55

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Mostly all of them, depending upon what you want... Be specific.... Good noises do come out of an early 90's Honda VFR 750 though. V-4, gear drive cams.... Torque and fun without being to horsepower-y

XJDano > ptak appreciates old racecars 08/31/2014 at 15:56

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Dual purpose fire extinguisher. A friend of my father in-law finally got his buggy running and used a Hyabusa motor, but that will likely kill you.

I imagine you'll need some sort of chain driven motor? Unless you look into a shaft one like my Silverwing was. I'm no expert but good luck with your project.

Vince-The Roadside Mechanic > ptak appreciates old racecars 08/31/2014 at 16:01

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I saw find a weed eater motor and build it to go faster.

Joel Ness > ptak appreciates old racecars 08/31/2014 at 16:13

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The Suzuki sv1000 motor would be perfect. Think v twin like a Morgan three wheeler but overhead cam instead of push rod. You'll have a torquey, rev happy, loud monster on your hands.

Telumektar > ptak appreciates old racecars 08/31/2014 at 16:16

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How about some kei-car engines? I know they aren't that light or that powerful but they should be good enough. Also, some did came/come factory twin-charged.

They could be good for about 35 to 65 HP, which is pretty good for 150-200 kilograms.

ptak appreciates old racecars > Telumektar 08/31/2014 at 16:22

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Aren't that many around where I live. I was counting on finding a totaled bike or something I could weed out the guts from.

ptak appreciates old racecars > RWS Motorsport 08/31/2014 at 16:22

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I'm no expert but I think the R6 is one of those which I'd kill myself with ;) thanks though! I'll look into it anyways.

Joel Ness > Joel Ness 08/31/2014 at 16:23

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I know you can find them on eBay in various forms of completeness.

ptak appreciates old racecars > XJDano 08/31/2014 at 16:24

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I'm working with some really tight spaces here, but I think I'm going with shaft (it'll probably be split into sections connected by UV-joints). A chain engine can be modified to accommodate a shaft, right? I'm sure it's not easy, but I know a guy in my neighborhood who can do anything with metal.

mcseanerson > ptak appreciates old racecars 08/31/2014 at 16:26

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Not a motorcycle expert but what about the ecoboost 3 cylinder?

Racescort666 > ptak appreciates old racecars 08/31/2014 at 16:37

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Any sport bike engine from the 90s would be fine. The newer fuel injected bikes have tons of power which gets you into the "kills yourself" territory. I would look into what the legends cars run. I believe it is a 1000cc carb/air cooled Honda.

One thing to note: most motorcycles don't have reverse so that might be a problem.

The Transporter > ptak appreciates old racecars 08/31/2014 at 16:40

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Don't know if this will work for you, but you might want to look into the Morgan Three Wheeler drivetrain. They mated a Harley engine to a Miata 5-speed.

ptak appreciates old racecars > mcseanerson 08/31/2014 at 16:44

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smoochy smoochy <3

too expensive tho :( I'm kind of working on a budget here.

ptak appreciates old racecars > The Transporter 08/31/2014 at 16:44

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That sounds awfully expensive for me, but that is kind of a dream setup. A Harley engine would work wonders if I'm honest.

ptak appreciates old racecars > Racescort666 08/31/2014 at 16:46

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Great information, thanks! I'll look into this.

I hadn't thought of that :P at least it'll be funny when I get out in traffic to push it backwards. It's meant to be ultra-analog and spartan.

McMike > ptak appreciates old racecars 08/31/2014 at 16:47

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Motorbike-sourced motors don't offer you a reverse. However, most of them are integrated with the transmission, which make things easier.

Sounds like a fun project.

mcseanerson > ptak appreciates old racecars 08/31/2014 at 16:56

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From what I've tried figuring the price on these and from what I can see it's around 3k but yeah, I know what you mean, budget.

Telumektar > ptak appreciates old racecars 08/31/2014 at 17:02

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Ah, ok. Bummer :(

The Transporter > ptak appreciates old racecars 08/31/2014 at 17:09

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I'm not saying that you should purchase one from Morgan, just that you might want to look at how they did it. Harley motors and Miata engines are cheap on the used market. All that might be needed is an adapter plate.

ptak appreciates old racecars > mcseanerson 08/31/2014 at 17:11

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that and simplicity. I want to be able to fix this thing with a paperclip when it inevitably strands me on some backroad

Full of the sound of the Gran Fury, signifying nothing. > ptak appreciates old racecars 08/31/2014 at 17:47

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Some larger touring bikes, like the Honda Goldwing, have a reverse function. If I'm not mistaken, it is accomplished by driving the vehicle off of the starter motor.

Full of the sound of the Gran Fury, signifying nothing. > ptak appreciates old racecars 08/31/2014 at 17:52

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I've always been partial to the Suzuki water-cooled V-twins; my experience is limited to late '80s VS700 Intruder, but I imagine later ones are as good, if not better. Smooth, torquey, and forever dispelled my opinions of V-twins (all I thought of before were on HDs, and seemed rather crude and vibration prone). Perhaps there's an adapter that will allow you to use a conventional transmission, a la Morgan three-wheeler.

Racescort666 > Full of the sound of the Gran Fury, signifying nothing. 08/31/2014 at 17:58

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That is correct. It actually drives the motor backward. A Goldwing motor might be too big though. You could hook up an electric motor to drive you in reverse without driving the motor in reverse though. I'm envisioning a decoupled electric motor that you can drive with the transmission in neutral. Hypothetically, you could hook it right to the output shaft since output shafts usually don't spin that fast (maybe 10k max which isn't that fast for an electric motor)

Jeff-God-of-Biscuits > ptak appreciates old racecars 08/31/2014 at 18:09

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Thinking about it... If I recall correctly, the BMW K bikes were inline 3's and 4's, both mounted to drive shafts. I'm fairly sure that you could figure out how to stand them up in the front, and that would even give you a quasi-accurate form factor and a good shot at a side exhaust.

ptak appreciates old racecars > Jeff-God-of-Biscuits 08/31/2014 at 18:34

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Interesting idea, thanks, and good guess, straight pipes are a priority on this project. I'll see if there are any for sale around my area.

ptak appreciates old racecars > Full of the sound of the Gran Fury, signifying nothing. 08/31/2014 at 18:35

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Thanks for the advice, I'll think about it!

Full of the sound of the Gran Fury, signifying nothing. > Racescort666 08/31/2014 at 18:40

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I wasn't exactly recommending a Goldwing motor as it seems like overkill for this project. In the interest of simplicity I wouldn't run a separate decoupled electric motor, but instead wire up a switch to the starter so that it reverses the polarity of the starter motor on a temporary basis for pushback duties. Integral to this switch arrangement would be an ignition kill so that it doesn't try to start the engine in reverse. Of course, if it was a two-stroke engine, forget about that and you would have 5 or 6 speeds in reverse if you so desired...

Jeff-God-of-Biscuits > ptak appreciates old racecars 08/31/2014 at 19:08

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I was just curious, so I looked...

http://baltimore.craigslist.org/mpd/4607582577…

therotaryisdeadlonglivetherotary > ptak appreciates old racecars 08/31/2014 at 23:14

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Check out what Dave Coleman is doing with a Miata: http://www.motoiq.com/Projects/Mazda… . It might be a little more work than what you're considering, but it's good for ideas

bob and john > ptak appreciates old racecars 11/18/2014 at 18:45

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Suzuki SV650 motor.

650CC V-twin, tuned more for torque then a 600CC race bike mootr, has about 75 HP. it would be PERFECT for your project.

can be bought on ebay for ~500 last I checked