DEAN Harrison won the senior event on wet ground in the Spring National Road Races at the Oliver's Mount circuit in Scarborough.
The Mar-Train racer from Bradford, riding the all-new 1000cc R1M, gave Yamaha UK a dream start to the 2015 road-race season.
He had to overcome the earlier disappointment of finishing third in the junior A race behind Ivan Linton and Lee Johnston.
Harrison said: "I was disappointed with the 600 (junior) result and really wanted to give both the team and Yamaha a win on the R1.
"I knew the bike had the pace so pushed to hit the front early and see if I could pull away.
"It is especially pleasing when you look at the quality of riders behind me – and also the times we are all doing, given the conditions and time of year."
Team principal Tim Martin added: "What a fantastic start to the season. We are using the Superbike chassis with a stock motor at the minute, so there is so much more to come from the Yamaha R1M package as the season progresses.
"The fact that we have taken a brand new bike and won with it on day one speaks volumes about Yamaha and also the guys in our team."
Harrison could not repeat his success the following day, with Guy Martin of Grimsby the overall winner.
Meanwhile, Harrison's dad Conrad finished top in the F2 sidecars, while brother Adrian was fifth in the junior B event on the opening day.
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