Balance Screw Mod

Just thought I'd share my mod to that pesky balance screw that Keihin tucked away between the throttle bodies on at least the early EFI Americas and Speedmasters, perhaps other models. It's not easy to get to and even when you do get to it, it is very difficult to turn.

The new screw was cut from an extension screw driver bit that was annealed to remove the hardening. One end was turned to 4.5mm and threaded to 4mm with a 0.5mm pitch. Not a common size outside of carburettor world, so if you want to do this mod, your average tap and die set won't have it - for Australian readers I got the die from Gasweld (SKU 514163).

The other thing that is handy is a fine rachet. There's not a lot of room to swing the handle and a lot of indents per turn makes the job easier. Also, best to have the rachet direction lever on top. I have one that is on the side and because there is so little room I kept bumping it, changing the rachet direction - sooo frustrating!. Mine is also magnetic. For Australian readers I got it from China via Alibaba.

The screw in the pic is a first (failed) attempt at single point threading the screw because I did not immediately have the correct die for the job. I forgot to take a pic of the next iteration before fitting it...but you get the idea.