Hi. I have 1987 Sportster converted to 1220. Everything was ok after the conversion. Now - after 4 months of riding - I feel that engine is not running smoothly. It's ok while accelerating, but during peaceful moderate ride I feel kind of pulling (at about 2200-2600 rpm) and I see turbulent movement on my tachometer. Decreasing speed is also uncomfortable. The engine is twitching.
I tried everything - 3 different carbs, different nozzles, clutch adjustment and I still feel it. I heard its bad old fuel, so I cleaned my previous carb and tank. It's much better but the problem still exists. What is it?

 

I saw something today.
I have automatic promary chain adujster. Working good.
Its look like: clutch many times is some faster from my crank shaft and chain is not tense on the upper side. This is no sense.
HALP

 

Maybe you have some tight links in the chain. Check each link for freedom of movement. You may also have a loose chain. When is the last time that you adjusted it? How many miles on the chain?