Rich, I have this question as part of another one of my posts, but I believe you will be able to provide the best answer to the question. I tried searching, but I didn't get anything obvious that got into the meat of subject. The bike that may get the spacer is a 2002 kx 125, fmf fatty, jetted clean, 12/51 gearing, boyesen dual stage reeds, otherwise stock w/new top end. So, here ya' go.......
Now, I have a question about the torque spacer: How does it work?? It seems like it would reduce the crankcase compression by adding volume which could reduce the bottom end power(?). So, what change does it bring about as opposed to not using one? Unless I am totally wrong, but it seems that the spacer is installed between the reed block and the case, which would increase crankcase volume? Or is the spacer installed between the carb manifold and the reed block, increasing the volume behind the carb? I might forward this part to Rich....
B.