i also hear they were quite dangerous to use,some people said that their chain broke alot of the time injuring themselves,is that true?Hi Antonio,, a jackshaft is used to relocate the drive force from left to right side, to offset the chain to help align with the rear, and/or to further reduce the drive ratio (as in use with 4 stroke engines)
examples: from the engine, there is another geared shaft to put the drive to the pedal sprocket on the right side, so you can use the bike gears ("shift kit")
4stroke: from engine, a chain or belt goes to a bearing supported shaft with 2 gears, then another chain goes from there to the rear sprocket, same side. unlike a 2 stroke China engine, 4 strokes need further gear reduction or else you would need an 80-100 tooth sprocket lol
wide engine: chain to jackshaft, then a 2nd chain closer to the frame to align with the back sprocket.
do you need one? depends on your engine of choice. want to shift your motor gears? (2 stroke/ebike) SickBikeParts has the best kit
What is a jackshaft? i heard it was a mod but what does it do and how it works, also if its worth getting 1