Having an issue with my '04 1200R under light acceleration between 1700 and 2000 RPM. Only shows up when it gets up to operating temp, like after cruising around town for an hour or so. It will miss out and ocassionally ping severely only in this RPM range. Above it or below it no problems. It's very annoying, as it lurches and bucks. Just showed up in the last 1500 miles or so. Current mileage is 17,500 miles. I just installed new plugs, and changed the slow jet in the carb from the stock 42 to a 45, and no change. I haven't made any changes to anything else recently. Only changes from stock are drilled out baffles in the stock mufflers, and a replacement style K&N air filter all of which have been there since about 1000 miles. I thought it was just a fueling problem, but the pinging doesn't fit with a fueling issue, does it? This is not under heavy load, but just light acceleration like when upshifting after rounding a corner, or just getting to speed going down the street. It's a very precise range when it gets warmed up and starts this annoying behavior. Anyone seen this before?

 

I see you rejetted. Did you drill out the plug to let you get to the adjustment screw? All CV carbed harleys have the same problem. Start here and see if this helps.

http://www.harley-performance.com/ha...arburetor.html