When riding, throttle will stay in open position before letting go and springing back to closed. Obs I only test this with a hand close by...it feels like its on cruise control momentarily, but I don't have C Control.. I have looked, and see nothing that stops it twisting and springing back / I can see metal handlebars between brake housing and grip. Does not stick when not being ridden. then it twists and returns freely. Feels like a sleeve tube with grit under it. I can open and close throttle easily but its just not 100% when riding. I realise it could be a MOT failure but they only test if it springs back, not what happens when its being ridden. Same happens when heated grips on or off. Not changed handguards or installed anything new. ideas? oil down the side to lubricate?