Scottys bikes

Scotty

New Member
Jul 5, 2008
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Melbourne Australia
I have made many motorized bikes over the years and would like to show you some of them.
I made this one about 5 years ago, The engine was noisy, smelly and unreliable but this build made me see the light. Running the motor through the gears is the only way to go! (^)
 

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NunyaBidness

Active Member
Jun 29, 2008
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memphis tn
is that a front free-wheel system? and if not, how in the world did you manage on the pedals?
that bike is an inspiration thank you for posting pics of it and if you have any pics of current bikes I sure would like to see those as well
 
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Scotty

New Member
Jul 5, 2008
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Melbourne Australia
This bike drove the pedals via the left crank, the motor freewheeled if off so I didn't have to turn the clutch or chain. It wasn't too bad pedaling constantly until you get to a tight corner.(you have to pull the clutch in to stop the pedals turning and catching the road.) I seem to remember a top speed of 84kph down a slight hill (50mph?) although I was also pedaling my butt off.

The later bikes all freewheeled for safety but I have since changed to GX35 Honda power.

I have to find some more pics...
 

NunyaBidness

Active Member
Jun 29, 2008
1,062
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38
memphis tn
wow
just wow
I'm having a hard time getting my head around that
a few years ago I was in South Carolina with a friend and we went riding our mountain bikes. no motors on 'em. we went up this long curving hill, not a very steep one, but it was very long. I asked my friend if we would be coming back the same way, he said yes we were. after we got to the top and a little ways past it I set my cycle computer to show my max speed as the largest number for when we went back.
the downhill ride was the fastest I have ever been on a bike. 42.5 miles per hour was the reading as max speed so I had to have held it at least 4 seconds. the bike was going so fast that I could not pedal any faster.
I truly admire your skills
 

Scotty

New Member
Jul 5, 2008
32
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Melbourne Australia
:D The car I was overtaking at the time had a confused driver too.

Im used to going much faster on my motorbikes but I find taking this or any machine to its limit to be just as thrilling.
 

sisdavid

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Mar 31, 2008
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Daytona Beach
What kind of engine is that and where did you get it. I know someone who has a similar engine. That is a good smoothe engine. Where did you get it?
 

Scotty

New Member
Jul 5, 2008
32
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Melbourne Australia
I dont know the brand other than Chinese. Its a Fleabay special 49cc 2 stroke.

I changed to a pocket bike 49cc 2 stroke on the next bike but it went too fast.

Now I use the honda GX35 4 stroke which is perfect, 100km to the litre (or 240mile to the gallon I think), at about 30mile/h average speed, and no stinky exhaust.
 

Scotty

New Member
Jul 5, 2008
32
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Melbourne Australia
The commuter, I got this up to 70km/h the other day on a test ride.
This is my first sale, to a mate at work. I fabricated the frame and the gear train. The motor and pedals both freewheel again.
 

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DasKapitan

New Member
Jul 27, 2008
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Birchwood, WI
www.cetaceanmarine.com
Scotty,
Your bike are works of art :)
Could you please elaborate on your reduction gearbox and mounting method utilized on the Honda GX35? Also after having a GX35 in hand, in your opinion is the fuel tank removable and could fuel be supplied by an external tank?
TIA
 

Scotty

New Member
Jul 5, 2008
32
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Melbourne Australia
Sure.
The engine is bolted directly to a 3mm plate which is welded to the frame. This motor wouldn't fit in a standard frame so I designed the teardrop shape to fit it.

The reduction box is an ebay item from a pocket dirt bike, same mount as the GX. Gocart sprockets and chain down to the freewheel jackshaft.

The fuel tank wouldn't fit and is too small for any great distance so I use plastic camping fuel bottles as you can see mounted under the motor. These use the existing lines and filter but the tank must breathe so I drilled an extra hole in the cap I made. I get 100km to the liter at 50 km/h as a rough guide.

These are great engines, perfect for this application, much cleaner than the 2 strokes, about as efficient as you can get too. I have had the carby ice up in cold weather but you would get that with any small engine I guess. I can highly recommend the GX.
 

DasKapitan

New Member
Jul 27, 2008
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Birchwood, WI
www.cetaceanmarine.com
Scotty.
Thanks for the info.
My goal is to try to place a four stroke in-frame on a worksman cruiser with a NuVinci rear hub.
I'm now looking at using a Robin EH035. Subaru Robin - Features and Benefits Its lubricating system is such that the engine doesn't need to be upright. Its also built better, cast iron sleeve and so forth. It has the same diaphragm type carburetor as the Honda. Do you think a gravity feed fuel tank would work above these type of engines?

There must be an industry standard for couplings/gears that attach to these class of engines. Can't seem to locate it though. I hadn't even considered pocket bikes until your thread. Again thanks. After searching I found a couple of providers of reduction boxes similar to yours. The covers look different. X7 pocket bike transmission, FS529 gear box, cvt, parts for chinese pocket bikes & Pocket Bike Parts, Gas Scooter, Mini Dirt Bike and Mini Chopper Parts for sale. There's no information on them regarding their actual reduction ratio. If I assume your gear is the same, enclosed chain type, as the above one for an X-7 pocket bike, what was your reduction ratio for planning purposes?

One other question if I may. Are you free wheeling on your jack shaft and just used two right side crank arms on a three piece to gain a sprocket on the left side?

G-Day DasKapitan
 

Scotty

New Member
Jul 5, 2008
32
1
0
Melbourne Australia
The Honda GX35 can run in any orientation also but I was looking at the robin myself for the cast iron sleeve. Either will work with a breathing tank mounted anywhere.
The second gearbox is the one I run, 3 to 1 reduction with a dual chain enclosed with grease. The other one seems to be thinner which may help. Welded straight to the sprocket that comes with the box is a 9 tooth gocart primary then down to an 80 tooth mounted to a freewheel. I only run 9 gears at the back so I used a granny 22 tooth and stepped down the crank with a 16 to 40, swapping the cranks around.
Now when I pedal only, the 80 tooth freewheels and when I motor only the 16 tooth freewheels. I can also run both together which works best as the Honda doesnt have much torque and my legs have plenty.
A NuVinci would work great instead of a cassette as you get a greater range and probably better power transmission I suspect. (I have had some trouble with the chain skipping at top speed in 8th and 9th and it isn't quality related.)