The following have been recommended by regulars. Someone in rec.motorcycles does a survey of catalog operations and publishes the results in table form every blue moon. Chaparral and Kirk did well in this report, but Superior Cycles was not listed. I have personally used Surdyke, Chicago H-D & Zanotti a couple of times and while the orders don't come rocket fast, they were correct and fairly priced with the 20% discount.

Surdyke Harley-Davidson - 20% off online orders

Chicago Harley-Davidson - 20% off online orders

Zanotti  - 20% off online orders

Chaparral Cycle Supply -- good selection and prices. 800-841-2960

Dennis Kirk -- good selection, fair prices. 800-328-9280

Superior Cycle -- good prices. 516-421-1655