Hi Norm,
I don't remember any knocking noise in my PT conversion to the FC 24. It was a bit of a noisy muffler so its not easy to tell. There is a slight belt whirr maybe because the automotive fan belt I am using has the cogged profile in the Vee.
It might be worth having a look at the spindle. In a well-worn 24 like mine, the sides of the vee are showing quite a bit of wear so there is a definite lip on the pulley from the belt. I was a little worried about it because that is one part you will not get. It does not seem to cause a problem though.
Good luck,
Jeff
