A guy named Justin contacted me when he saw this blog. We talked, and he turns out to have a past experience with building motorized 2-wheeled vehicles. So here is an interview we had!
Chris: Good evening Justin, I'm glad we could talk!
Justin: Hello, Chris.
Chris: So, lets start things off. Tell me about your
projects that you've done before?
Justin: My first project was modifying a mountain bike to
accept a gasoline engine. It was a good learning experience and motivated me to
learn how to machine simple parts, weld, and also overcome a number of design
obsticals.
Justin: My two most recent projects involved modifying a
Jawa 210 moped to accept a larger, more powerful engine and modifying a Honda
C70 Passport to accept a (again) more powerful GY6 type engine.
Chris: So what first inspired you to add an engine to
something that as built to take man power?
Justin: I bought an ugly scooter and decided to modify it to
go faster. I realized that this vehicle was limited by its design, so I decided
to transplant it on to a different frame. I also have a love of early 20th
century board-tracker style motorbikes, so this was an attempt to create
something that looked like that. Moreover, I just thought it would be awesome.
Justin: Also, pedaling is for suckers.
Chris: Haha, that is very interesting. What types of
problems did you run into in this transformation?
Justin: The largest problem I had was how to tansfer the
power from the engine to the rear wheel. The drive sprocket was on the left
side of the engine, but the bicycle's rear wheel sprocket was on the right
side. I ended up fabricating a jack-shaft transmission near the pedal area to
accomplish this and also get a more usable gear ratio.
Chris: How much planning did you do? Was it easier to
encounter problems as they came, or plan ahead with what you knew?
Justin: There was very little long-term planning. I wanted
to preserve a certain amount of asthetic appeal and performance, but that was
the extent of it.
Justin: I'd more or less build until I reached a problem,
and then solve it.
Justin: Technical plans are largely useless if you don't
have the tools to make use of them.
Justin: And, they usually go out the window as soon as you
reach a problem.
Chris: So up to today, what problems have you had? Would you
say it is easier to build a vehicle around an engine, or an engine around a
vehicle?
Justin: The engine is the deciding factor in most cases.
Especially with gasoline engines. Engine mounts and the geometry of the exhaust
system, intake, ground clearance, and the location of the power output shaft
are the designer's straightjacket.
Justin: Electrical engines are more forgiving because they
have no intake, exhaust or oil supply. Also, they can be mounted to nearly any
flat surface.
Justin: Wires are flexable and can be made to any reasonable
length, which definitely helps.
Justin: Electrical motors are also smaller and lighter,
generally.
Chris: So you agree with me in the idea that electric
engines are a better option than gas?
Justin: Hah.
Justin: It depends on the criteria
Justin: electrical engines are not without their problems.
I'd say, however, that for a 'first project' an electrical motor is a better,
easier idea.
Chris: But the fact
that electric systems have a larger choice of charging options, wind power,
solar energy, and hydroelectric energy, does seem better than gas, correct?
Justin: If it's an environmental issue, yes I absolutely
agree. Logistically, it's currently easier to fill a tank with gas than it is
to find a charging station.
Justin: I'm hoping that society will move toward electric
vehicles and that public charging stations become more commonplace.
Chris: You have a valid point there. Hopefully within the
next 10 years we will be more dependent on electricity and less dependent on
oil.
Justin: We can hope. As it stands, the major limiting factor
for electic vehicles is the battery.
Justin: The expense, size, weight, lifespan, and storage
capacity of modern batteries is not all together that good.
Chris: That is where we are today. Lead acid batteries are
stable, cheap, and thus prevalent, but very large. Lithium power is a better
solution, with its much smaller size, but it is unstable, known to explode, and
is "broken", per say, if you drain it to 0%.
Justin: Ah, yeah. that's about accurate.
Justin: Lithium batteries like to stay charged, that's for
sure.
Chris: Well, I guess this is the point in the interview
where you get to ask me any questions you might have.
Justin: I'm unprepared :(
Justin: haha
Justin: I don't think i really have any.
Chris: That what I wanted to hear!
Justin: Oh, just a few tips for your project... make sure
that the sprocket on the motor's drive shaft is aligned with the sprocket on
the rear wheel. If it's not, it's a good way to throw a chain. Also, don't
design it to have a tight chain, as is... try to engineer in a chain tensioner
instead. maybe rip one off of a bicycle.
Justin: hard learned lessons, believe me
Justin: haha
Chris: Actually, when I bought my frame, it was designed with
a tensioner, which was a real plus.
Justin: excellent
Justin: chains stretch over time, so it's a must... unless
it's like a motorcycle that has an adjustable rear wheel.
Justin: that accomplishes the same thing. I'm assuming that
your's doesn't.
Justin: well, anyway. email me if you have any more
questions or whatever.
Justin: oh, what's the link to your blog? I haven't seen
your progress in quite a while
Chris: Thank you for your time Justin, and I will contact
you again if I need help.
Justin: no problem
It was a good chat, and Justin is a smart man. I look forward to referring to him for help!
