Motorcycle Repair: 94 sportster knock, start ups, great shape

Question
QUESTION: Mike,
I have a 94 XL that was just purchased not too long ago that has what sounds like a knock in the top end in the first ten or so feet when starting off until the RPM's pick up. I kind of sounds like a diesel engine when first accelerating. This is my first Harley, so I was wondering if I have a problem or is this just bogging down until the RPM's pick up when starting to ride? The bike was sitting for a couple years before I purchased it. It has 6300 miles and in great shape, well taken care of.

ANSWER: When the bike is sitting ideling, do you hear the knock?
Mike

---------- FOLLOW-UP ----------

QUESTION: No just in the beginning of acceleration, and I would say that when the engine first starts to fire on start up there is a loud knock, but just one,and only if the engine catches just right, maybe 1 out of 50 start ups, it's rare.

Answer
Without hearing the noise, its hard to determine what the noise is.
It can be just a piston knock or a pushrod ticking or your primary chain is to loose. Worse case, it can be a rod going out, which would make noise at low RPMs or at idle
Good luck and happy riding
Mike