Hi guys having issues with a sticky valve. Tried flushing the motor out and using engine flush ect. Still gets stuck everytime I go over 3,000rpm. Had bad knocking yesterday when it happened. Hope I havnt bent or done damage. Anyone know how much to fix it? can do myself. Or would the cost be not worth it? Just get a new motor ect. Dont want to buy all the parts to find out theres more wrong with it. Cheers