I'm not sure about HD, but many other vehicles can be cleared by disconnecting the battery for a few minutes.

 

I found this on the net, + if the 'Engine Check Light', does not stay on it is OK to leave the P0151 if you have checked the following,


"This is the exerp from the 2008 Harley Dyna Service Manual that talks about the 131/151 codes.

You will note that they tell you to "clear and ignore" the codes. Their reference is primarily associated with break-in, but it seems strange that something that is acceptable at 999 miles because an issue at 1001 miles.
Please notice HD's list of causes for 131/151 codes.
Poor Connections
Dirty Injectors
Loose O2 Sensor
Loose/Leaking exhaust
Engine misfire
We see the last three causes as primary candidates to trigger the codes, especially with the IED's in place.
We also have evidence from a state run EPA test laboratory that codes are very likely to be triggered just after initial startup, between the time the engine starts and it revert to normal closed loop operation". (This is what I gleaned from the net). For more info take a look at:


http://www.nightrider.com/parts/131_151_explained.htm




Hope this is of some help.