Monday, March 28, 2011

Triumph Project

Jack shaft assembly welded in. 260mm tire. 1 1/8 x 132T belt. Still need to weld in the chain tensioner. The shaft will be threaded on each end and have nuts to keep it all together.


  1. I will be using a 280 back tire. iwill also be using a exile chopper sprocket brake. If you make a sprocket brake I will purchase one from you. would it be possible to run chain side by side? I would like to have the belt and chain from the motor to the jack shaft. I hope you can shed some light on this. You have the best descriotion of a jack shaft I have ever seen. if you can i would appreciate it.
    want to use a belt but I would like the cleaner look if possible

    Thank Robert

  2. I would like to tell you guys that what a web site you have going. Building bikes since the seventies. Wanted to build a jack shaft, after all these years when they said it couldnt be done without offsetting the motor which a third grader knows that something is going to be lopsided. Is ther any way that you could put the belt and sprocket on the same side? I am using a 18-5/12 280, I have twelve inches between the inside rails of the rear section, thats inside to inside. Thanks again for you expertice. Robert

  3. Thanks Robert. Shoot me an email at and I will do my best to help you with your project.

  4. I need to do a jack shaft on my bike. I see you have done it but I have no idea where to begin. Can you help me out? Its the last thing I have to do to get ready for paint and get down the road.
    Thanks in advance

  5. I started on my 73 Bonnie 750 way back in 1976..was gone for 3decades and am looking to come into the new style fatrear tire and longer stretch on my corbin gentry wishbone frame that has a Fury dualspring girder 16over.I knew the only way to get wide in the rear was with fabing a jackshaft to offset clearence.You have a very clean fab but was wondering about being able to adjust the tension from drive sproket on engine to jackshaft 2nd drive.Also what lubes the shaft and/or bearings?