Hello to all Harley riders out there. I've had my Sportster Custom for about twelve years, but have come up against a problem I've not been able to resolve yet, by online searches, or even asking at my local dealership. My bike has carbs, no fuel injection, and doesn't run really well in cold weather - say when it's below 6 or 7 degrees. It misfires, runs on one cylinder etc. Harley used to make an 'idle boost', or 'winter fuel enhancer' as they called it. An liquid you could add to the petrol and it would run fine. They no longer make it, and I haven't found a substitute for it yet. Does anyone know what I could use, and where I can get it?