limited throttle

[tripled up]

Hi all,
When my Spitfire is not running I have full throttle movement on the twist grip and the carb slides move freely. However, when the bike is fired up and ridden i can only get upto 1/3 movement on the twistgrip. Any advice/tips much appreciated. Thanks

[Dean Southall]

First, double check throttle cable for snags or cable adjusters snagging when cable wiggled.
Its more likely though that the slide is tight in the carb bore and as the body heats up it binds the slide. Could be that the carb is slightly overtightened on the mounting flange. Try backing off the mounting nuts half a turn and see if it stops the slide sticking. If not then get the carb out and check for bore ovality.