A couple of posters here mentioned how difficult this was and having pulled mine off to check if the bars were bent I couldn't agree more - getting the spring back in looked like an impossible Chinese puzzle. But having slept on it I found a solution I thought worth sharing:
Point one is if you don't need to disassemble the twistgrip then don't. Just loosen the screws enough to disengage the pin and slide assembly off.
Otherwise assemble the twistgrip off the handlebar with one end of the spring engaged in the sensor and the other end poking out of the handlebar hole. Its then relatively easy to use a screwdriver to push that end round till it engages in the housing. Then loosen the screws a few turns and slide the whole assembly on the bar being careful not to disturb the spring. Job done in about 10 minutes.
PS Remember the spring closes the throttle....
Point one is if you don't need to disassemble the twistgrip then don't. Just loosen the screws enough to disengage the pin and slide assembly off.
Otherwise assemble the twistgrip off the handlebar with one end of the spring engaged in the sensor and the other end poking out of the handlebar hole. Its then relatively easy to use a screwdriver to push that end round till it engages in the housing. Then loosen the screws a few turns and slide the whole assembly on the bar being careful not to disturb the spring. Job done in about 10 minutes.
PS Remember the spring closes the throttle....
