Surly Instigator 66cc jackshafted mule

Discussion in 'Photos & Bicycle Builds' started by KCvale, Oct 2, 2014.

  1. KCvale

    KCvale Motorized Bicycle Vendor

    This Surly bike arrived as a frame and a whole bunch of other boxes of parts of the customers choosing so a bare frame build up to be a back woods mule.
    In short the guy wants to climb cliffs or 'trials' ride on it at a top speed of ~12MPH @ 8500RPM.


    I went with the SBP jackshaft shift kit and mount to keep that torque monster in the frame and move the output.
    You can also note the modified intake to make room for the carb in that tight frame, and that tiny 32T drive sprocket on the pedal chainring.

    Those disc brakes are cable pull hydraulic, each caliper has it's own fluid well and adjustment for sensitivity which worked out cool for the SBP dual pull brake lever, I just made the front a bit more sensitive than the back and with a 'school zone crosswalk' top speed it stops in about a foot or two.


    As mentioned he doesn't want shifting gears but has a cassette hub.
    The solution was just picking the right size rear sprocket and then just using the this cool packet of spacers to put just one sprocket positioned exactly in line.


    Both wheels are fixed in place with a removable axle and the back wheel and frame actually need something to fit where the derailleur was and the customer supplied a tensioner but it wouldn't hold up to the torque, nor would the HD Z 410 chain.

    The motor side has 415 chain but there is no room with the chain cross for 415 on both right side chains so I am putting on KMC HL710 1/2 link chain.

    I normally hate the stuff to work with and at $30 expensive, but the new HL710's come with cotter pin thing for a master to make it easy to use and using that chain this build needs no tensioner.
    Pics on that when we wrap it up.

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