Take one bottle of Spitfire Ale. Drink the bottle till empty. Put empty bottle in recycle bin. Take the cap. A stainless steel bolt and a large washer. Attached the cap to the washer. Peen over the edges of the cap around the washer which has the stainless steel bolt through it. You now have a hand made choke knob that cost around $10. Take the bike's choke knob off. Fit the one you have just made.