According to Official Guinness Records,
The record for longest distance covered by a motorcycle (with the front wheel taken off) on a tightrope was 50 m (164 ft) and achieved by Chen Shuangquan (China) in Taiwan, China, on 15 October 2007.
It was done for Zheng Da Zong Yi - Guinness World Records Special as an outdoor event.
For a complete list of 2007 records, please visit 2007 Guinness Records in China.