I checked the book "Our Harley Family Connections" and unfortunately there isn't a David Harley listed.
The book lists; William Harleyborn: 1796 in either England or Courtmacsherry, County Cork, Ireland. He moved to Mirimachi, New Brunswick in 1820 followed by his sister Mary Ann and brother John.His mother Ann (Bidder) Harley (she was Welsh) came after the death of her husband William Harley Sr.Ann died around 1835 in or near Vernon BC Willaim Harley married Ann MacLean Nov 19 1823 and their children were: Archibald, Eliza Ann, Prudence M, Susan Jane and Willaim Allan. All born in New Brunswick. The family moved to York, Ontario after 1832 and James H was born in 1834. Ann died a few days after James was born. Willam's sister Mary Ann married John Henry March 31, 1823 and had 9 children. William's brother John went to New Brunswick in 1823 and married Ann Coughlan Dec 12, 1829. They had 4 children: Frances, William C, Charles and Susan. Some of this family stayed in NB others moved to the Western US. The book starts with the The Harley British Connection but does not connect them to the Early North American family of Harleys. This is just a snippet of what this 187 page book contains.