4866 OTC Timing Plug - This threaded clear acrylic timing plug used in conjunction with a timing light allows for viewing the crankshaft timing marks without oil spraying out of the crankcase, typical during full advance RPM.  Fits all HD models.

Warning: This product may expose you to chemicals including lead which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov