I have a stock 1991 FLTC. Lifters were replaced about 2,000 miles ago with Harely B lifters, stock cam, replaced cam bearing, and it has stock Harley non adjustable pushrods. The bike has recently developed a detectable tapping noise (sounds like a loose pushrod or bad lifter) only between 2,700-3,000 rpm. No noise in anyother ranges. What could cause the noise in that rpm range only. Any ideas appreciated. Thanks!!

 

Have you been able to isolate the noise, either a stethescope or a long screwdriver held up to your ear and placed on various parts of the engine. Oil flow good? - did you check the screen?

The fact that it only does it between that narrow RPM range is odd, a bad lifter will generally make some noise most of the time. I had a tap once that sounded like it was in the valve train until I took a good listen, it also only happened in a certain RPM range and then went away...It was the primary chain lightly tapping the case. Try to find where it is loudest in the motor...

Ds

 

I'm unsure of noise. How about pulling lifter screen and see if any debris is in there.

Could it be a loose exhaust shield?

 

You had the bike apart 2,000 miles ago to do the cam job, including the exhaust system, I'm presuming. Have you rechecked the torque on the exhaust nuts at the cylinder head? With new exhaust gaskets, I find the gaskets take a set after a while and the nuts need re-tightening. A very small exhaust leak at the cylinder head can make the exact noise you are describing.

Not saying that's your problem, but it's worth checking before you tear into things again.

 

This right here... had the same thing happening. Found a loose exhaust nut, re-tightened it... no more tap.

 

So did I. That's how I knew it.

 

It will be a few days before I can look at bike, but I am going to check nuts on exhaust pipes. Hopefully this is it, if not I will have to go further. Thanks!!