At low speeds and under harsh acceleration ie at high torque, there is a clunking noise.
Is this normal for the centra compensator performong its function or does it mean the belt is slipping (unlikely)?
If you query the S&S site as well as searching through all of the posts on this site, you will find that using the engine under any load below 2,700 rpm is a no-no. Aside from taking off from a start in first don't do it! Really! The group of people who have complained most loudly about the life and noise of the compensator have, for the most part, been lugging their engines. Lugging this motor is hard on the compensator, which is there to smooth out the pulses from that great big hammering V-Twin located in the front. It is designed to absorb the shock and smooth out the pulses so it doesn't eat the transmission. Just upping the rpm's will smooth it out to a great degree. Try it.
The operating range on this beast, is really between 3,000 and about 4,500 rpm. That is very narrow but you have gobs of torque to compensate. Below 3,000 you will get noise and bucking and general unpleasantness from the compensator. Above 4,500 the engine will have a tendency to get a bit ragged. It will do more, but I wouldn't push it. Shift into a higher gear.
In my experience, the sweet spot is around 3,500 to 3,800 rpm. Very smooth and easy. It could loaf like this all day without strain. You can accelerate easily or back off and slow down just using the engine.
In one of my posts, I likened it to a diesel. I still stick to that. A diesel doesn't lug well and cannot reach high rpm's but, due to the massive amount of torque you have on hand, can do amazing things within its capabilities.
An Addendum: In my estimation, the tachometer is more important that the speedometer. The speedometer is adjusted so that it will read probably under 5% of your true speed. Trust it as far as you can throw it. Like the gas gauge, that is totally accurate when you fill it up and it reads 100%. Anything after that is a guess...
The tachometer is accurate. It is your friend.
