A gyro is a system that allows a BMX rider to spin his handlebars around infinitely without binding or twisting the bike's brake cables, which still allow the bike to brake when needed. The system is a popular one, coming standard on many BMX bikes on the market. However, the system is also very heavy and does not provide sufficient braking power for many riders, so in an effort to lighten the bike and increase braking performance, remove your gyro system and replace it with a straight cable, a procedure you can perform at home.
Set the bike up on a dedicated work stand if you have one. This will make removing the existing gyro set-up much easier. If you don't have a work stand, prop the bike on or against something so that it won't tip or fall while you work.
Using a basic wrench set, remove the gyro mechanism by loosening and removing the handlebar stem, loosening the rear brake cable stop and pulling the gyro free of the head tube. Remove the gryo brake cable from the rear brake lever, then reattach the handlebar stem and you're ready to install the straight cable.
Attach the head of the new rear brake cable to the rear brake lever cable stop. Reset the brake lever barrel adjuster by twisting it clockwise, tightening it against the lever body. Slide a piece of new rear brake cable housing three to four feet long onto the rear brake cable. Set the housing in the rear brake cable housing stop on the down tube of the frame. Turn the handlebars to be sure that they will still spin one full rotation without binding or pulling at the cable.
Use two 10-millimeter combination wrenches to attach the U-cable clamp to the end of the rear brake cable. Set a new U cable in the cable stop on the left brake arm. Run the U cable through the U cable clamp and tighten it in the cable stop on the right arm of the brake.
Take the bike for a test ride in a safe area. Check the rear brake to be sure that it stops the bike quickly and effectively. If the brake is too loose, turn the barrel adjuster of the brake lever counter-clockwise to tighten the brake cable. When the brake is adjusted properly, head off to the skate park for a nice, long trick session.