Page 2 of 2 FirstFirst 12
Results 11 to 13 of 13

Thread: XB12r gearbox parts.

  1. #11
    Senior Member
    Join Date
    Apr 2018
    Posts
    153
    Aidan you need new parts not undercut gears. Undercutting is fixing a symptom not a problem. Replace drum, selector forks and selector fork shafts. in properly functional transmission there is no load on the gears side to side hence no need to undercut.
    Here is a good explanation that I found helpful.

    https://www.youtube.com/watch?v=GsgiaAMc7cM

  2. #12
    Senior Member Cooter's Avatar
    Join Date
    Dec 2012
    Location
    Crawling up your skirt
    Posts
    10,877
    I have never held a Buell transmission in my hand, but I know for a fact other V-twins have undercut gears stock. Including the similar Harley XL (Sportster) transmissions (1-4* depending on gear and year), and can confidently assume that a similar engine built with considerably more torque (like Buell) has gears undercut stock. I'll do some research to find out definitively.

    Gears with no undercut will work in light duty/ low-torque applications, but don't assume that's true of all transmissions. In high torque applications, the shift forks and drum are unable to control the sideways force of the gears from the gear shafts deflection. The slight undercut angle of the dogs makes sure to hold the gear pair together under high torque conditions. Too high an undercut (7*+) makes for hard shifting.

  3. #13
    Senior Member
    Join Date
    Apr 2018
    Posts
    153
    The point of my post is to make sure folks dont go out of the way and send the gears to get them cut. Just replace with stock components and if there is still a problem with popping gears then undercutting should not be a solution. Rather look at the forks, fork shafts, drum or check make sure the input and output shafts are parallel. Those are the things that make, other wise perfectly functional transmission, miss behave.
    There is very little to no side load during operation. Forks and drum do not hold gears in place. They are there to select which gear transmits power, they are not designed to hold gears in place, period.



Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •