MikeJ
Member
Hi Everyone -
Here is my latest build (read: prototype) on which I have been spending a few hours here and there over the past few months. Photos should be attached.
Comfort for long-haul bike rides was a major factor in this build. A previous build using a 2-cycle engine rode well on smooth surfaces, but I took a beating on rough roads. With this frame, I got balloon tires, shocks up front and in back, a better seat, and a less vibrating engine. There is almost no beating sent to the rider. The rear wheel frame pivots freely at the dropouts of the leading frame.
I took frames of three bikes and combined them together. All three were steel frame mountain bikes: A 1994 Mtn Tek Extreme for the main frame and a Specialized Hardrock for the back part. The third bike contributed very little. All other parts are new out of necessity or desire:
Front Rock Shox Dart 2 up front from a local bike dealer,
79 cc 4-cycle engine from Harbor Freight,
Extra-wide bottom bracket and drivetrain pieces from Sick Bike Parts,
34 tooth MegaGear assembly from Sick Bike Parts,
Derailler, chains, and wheels from a local bike dealer,
Gas tank, throttle control and cables from Piston Bikes,
Scooter shock from ScooterParts4Less.com,
Copper exhaust line and lots of hardware from Ace Hardware,
Bearings from local industrial parts outlet,
Engine platform and lots of JB Weld from Home Depot,
Centrifugal belt clutch from MaxTorque,
Multi-horsepower rated drive belt from Auto Zone.
Yellow electrical tape covers a couple of places that I have to touch-up with the yellow paint.
There was no additional hot welding done at all to this build. I can remove the back pivoting frame and rebuild a standard-length bicycle out of everything you see in the pictures.
The bike rides nice without the engine and drive train. Today's test ride was with engine in place but without engine power. With an engine this wide, I will not pedal much; just enough to get it moving before engaging the clutch. That MegaGear will be a necessity when taking on long hills or pedaling without the engine. Going on flat land, gears 3 and 4 will be nice to have. I think it will ride like an underpowered early-60's Cadillac.
The bike's absolute length is 84 inches; won't fit nicely in a pickup truck.
The horizontal bar is 33 inches above the ground at back of gas tank,
Tires are puncture resistant; 26 inches by 2.3 inches.
Both wheels need disc brakes; a rear wheel disc brake assembly is on order.
The engine platform is dense oak: 2.25" x 5" x 18". It is JB Welded to the frame and compressed together also by side-to-side bolts.
Pillowblock bearings for the jackshaft are overkill, but they will not die.
The bike as you see it (dry tank) weighs 87 pounds: 47 up front and 40 in back. (It must be the fast drying paint that is adding all that weight.) Weight creep is like middle age; Every extra part may add strength and functionality, but also an extra pound, or two, or four. . . .
It still needs a kickstand, speedometer, tachometer, some lights that will be seen a half mile away, and a rack extending over the back wheel. There are only a few more parts to be installed. I already have a good, DOT-rated high-visibility motorcycle helmet, a bright yellow jacket and leather gloves.
The pulley ratio is 3:1; the jackshaft to bottom bracket ration is 48:10. This works out to about a 15:1 drive train ratio. This is good; I computed that low-30 mph range will be little work for the engine.
As big and heavy as this build is, I should park it in Compact Car Only spaces.
I have more pictures of the in-progress build, but I figured a few here and more in the future will be welcomed. Let me know what you might have done to make this motorized bike better (like avoid excess weight).
MikeJ
Here is my latest build (read: prototype) on which I have been spending a few hours here and there over the past few months. Photos should be attached.
Comfort for long-haul bike rides was a major factor in this build. A previous build using a 2-cycle engine rode well on smooth surfaces, but I took a beating on rough roads. With this frame, I got balloon tires, shocks up front and in back, a better seat, and a less vibrating engine. There is almost no beating sent to the rider. The rear wheel frame pivots freely at the dropouts of the leading frame.
I took frames of three bikes and combined them together. All three were steel frame mountain bikes: A 1994 Mtn Tek Extreme for the main frame and a Specialized Hardrock for the back part. The third bike contributed very little. All other parts are new out of necessity or desire:
Front Rock Shox Dart 2 up front from a local bike dealer,
79 cc 4-cycle engine from Harbor Freight,
Extra-wide bottom bracket and drivetrain pieces from Sick Bike Parts,
34 tooth MegaGear assembly from Sick Bike Parts,
Derailler, chains, and wheels from a local bike dealer,
Gas tank, throttle control and cables from Piston Bikes,
Scooter shock from ScooterParts4Less.com,
Copper exhaust line and lots of hardware from Ace Hardware,
Bearings from local industrial parts outlet,
Engine platform and lots of JB Weld from Home Depot,
Centrifugal belt clutch from MaxTorque,
Multi-horsepower rated drive belt from Auto Zone.
Yellow electrical tape covers a couple of places that I have to touch-up with the yellow paint.
There was no additional hot welding done at all to this build. I can remove the back pivoting frame and rebuild a standard-length bicycle out of everything you see in the pictures.
The bike rides nice without the engine and drive train. Today's test ride was with engine in place but without engine power. With an engine this wide, I will not pedal much; just enough to get it moving before engaging the clutch. That MegaGear will be a necessity when taking on long hills or pedaling without the engine. Going on flat land, gears 3 and 4 will be nice to have. I think it will ride like an underpowered early-60's Cadillac.
The bike's absolute length is 84 inches; won't fit nicely in a pickup truck.
The horizontal bar is 33 inches above the ground at back of gas tank,
Tires are puncture resistant; 26 inches by 2.3 inches.
Both wheels need disc brakes; a rear wheel disc brake assembly is on order.
The engine platform is dense oak: 2.25" x 5" x 18". It is JB Welded to the frame and compressed together also by side-to-side bolts.
Pillowblock bearings for the jackshaft are overkill, but they will not die.
The bike as you see it (dry tank) weighs 87 pounds: 47 up front and 40 in back. (It must be the fast drying paint that is adding all that weight.) Weight creep is like middle age; Every extra part may add strength and functionality, but also an extra pound, or two, or four. . . .
It still needs a kickstand, speedometer, tachometer, some lights that will be seen a half mile away, and a rack extending over the back wheel. There are only a few more parts to be installed. I already have a good, DOT-rated high-visibility motorcycle helmet, a bright yellow jacket and leather gloves.
The pulley ratio is 3:1; the jackshaft to bottom bracket ration is 48:10. This works out to about a 15:1 drive train ratio. This is good; I computed that low-30 mph range will be little work for the engine.
As big and heavy as this build is, I should park it in Compact Car Only spaces.
I have more pictures of the in-progress build, but I figured a few here and more in the future will be welcomed. Let me know what you might have done to make this motorized bike better (like avoid excess weight).
MikeJ