Put Drag Specialties Python3 slip-ons on my 08 1200C last sat (dealership put them on, not me). Bike runs great and sounds great to boot. Here's my question: bike has always pinged & knocked from day 1 even though I've always run Shell/BP-Amoco/Exxon 93 oct gas. NOT ONE PING OR KNOCK SINCE THE NEW PIPES/SLIP-ONS WERE INSTALLED. New pipes are 2", old stock pipes are 2 1/4". Smaller pipes with a freer flowing (higher air flow?) baffles which I thought would let more air through making the air/fuel mixture even more lean hasn't happened. Why did the pinging & knocking stop? Tracy I really like the slash cut looks too!