Jackshaft transmission options? jackshaft

holdenrodder

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australia, vic
hi, i need to build a bike to make the 25km trip to work every day, as i am losing my licence and theres no public transport in my rural area.... :cry:
im still trying to decide on a setup, and i still know very little, but im willing to learn. there is one reasonable hill on the way to work, so i was thinking a four stroke? any way, the main thing i wanted to ask was what transmission options are there other than a jackshaft setup? i was thinking of mounting another sprocket to a three speed hub, on the outer of the hub, and using that as a gearbox between the engine and the wheel? but im betting you guys have some better ideas, or can see the holes in my plan that i am oblivious to :D
thanks!
 
If you have a reasonable hill to climb and need to do so in all weather conditions and want dependable reliability, the best option is a SickBikeParts shift kit, which has been designed to work with 2-stroke and 4-stroke engines, depending on which kit you purchase.

Best to grab the delux version as it contains all the necessary tools.
 
hi, i need to build a bike to make the 25km trip to work every day, as i am losing my licence and theres no public transport in my rural area.... :cry:
im still trying to decide on a setup, and i still know very little, but im willing to learn. there is one reasonable hill on the way to work, so i was thinking a four stroke? any way, the main thing i wanted to ask was what transmission options are there other than a jackshaft setup? i was thinking of mounting another sprocket to a three speed hub, on the outer of the hub, and using that as a gearbox between the engine and the wheel? but im betting you guys have some better ideas, or can see the holes in my plan that i am oblivious to :D
thanks!
Check out this approach. It uses a 33cc engine, and a pocket-bike CVT. At low speeds, the CVT is engaged, adding an approximate 2:1 reduction, in addition to the 3:1 gearbox. As the load decreases, the CVT ratio gradually shifts up to a 1:1

If you had a 6:1 sprocket reduction from the CVT to the rear axle, the bike would have a top end about 33 mph, and on hills, would have max torque at about 14 MPH.
 
thanks guys, any other options i should consider? im thinking of just gearing it right up with a reasonably torquey engine, and getting upto speed with the pedals. more reliability, cheaper, and i could use the exercise anyway
 
The cheap and easy way is a 2-stroke strap-on kit with the rear-wheel left-side sprocket ~$250, ...add bike and you're good to go! Not the way I'm going with mine, but you said cheap right? I keep hearing about guys going 50 mph+ with 66cc.

http://www.gasbike.net/bicycle-motors-2-stroke.html

I chose a new steel frame fatbike cruiser with a Preddy 79cc, SBP jackshaft, 3-speed hub shifter, discs, and other quality items to make it more reliable and to last longer, ...I'm into it for almost a grand already and it's not finished.
 
The easiest 3 speed Jackshaft would work with a CW rotation being driven from the right.
A 49cc Honda (or clone) 4 stroke with the 5:1 gearbox would reverse the rotation to give you CW.
 
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