Iam new to this group and a new owner of a '84 XLX. Having owned a few EVOS' that did not have the feel or sound of the old Harleys I bought this one. Its' a one owner,stock except for the air breather and has 65,000 miles. It ran good for the test ride and after a few rides it start spitting and backfiring and just got worst. So bad its not rideable. Put in a fresh set of plugs (CHAMPIONS RL82YC .040 gap) and to no avail. Before all this it ran strong, no smoke or strange noises. Any help is appreciated.