HONG KONG will be able to ride out the trade row between the United States and Japan without any serious economic impact, according to economists. Any downturn in demand for original equipment manufacturers or offshore Japanese plants would be marginal. The impact on Japan's recovery and US economic health would be slight, they said. Michael Martin, assistant chief economist for the Hong Kong Trade Development Council, said: 'I do not see any direct implications for Hong Kong.' Graham Neilson, economist for Asia Equity, said if the US were to succeed in opening Japanese car markets, the implications could be positive for other sectors of the economy.