* Nikkei down 4.1 pct for the week
* Toshiba tumbles on bigger-than-expected loss
* Yamaha soars 18 pct after raising forecast, dividend, announcing share buyback
By Ayai Tomisawa
TOKYO, Feb 5 (Reuters) - Japan's Nikkei share average fell for a fourth day on Friday and was on track for a weekly loss as investors are worried that a stronger yen could squeeze exporters' earnings, hurting automakers like Toyota and Honda in particular.
The Nikkei dropped 1.5 percent to 16,794.30 points in midmorning trade, after hitting an early low as 16,729.51, the lowest level since Jan. 26. For the week, the benchmark index has declined 4.1 percent.
The dollar traded at 116.89 yen, up slightly from overnight trade but not far from Thursday's two-week low of 116.525 yen. Investors braced for U.S. employment figures later in the day which might provide clues on the timing of the Federal Reserve's next move to tighten policy.
Toyota Motor Corp dropped 2.3 percent, Honda Motor Co shed 3.1 percent and Nissan Motor Co declined 4.0 percent.
"The biggest concern for the Japanese market now is whether the dollar will weaken against the yen further," said Yutaka Miura, a senior technical analyst at Mizuho Securities. "You don't know how U.S. stocks will perform after the jobs data release, so most investors are nervous."
The number of Americans filing for unemployment benefits rose more than expected last week, suggesting some loss of momentum in the labor market amid a sharp economic slowdown and stock market selloff.
Toshiba Corp dived 13 percent after it said it expects a bigger full-year loss than previously anticipated, amid mounting restructuring costs after a $1.3 billion accounting scandal.
Outperforming the market was Nikon Corp, which soared 8 percent after its net profit for the April-Dec period rose 28 percent. Following the announcement, Nomura Securities raised its rating to 'buy' from 'neutral.'
Yamaha Corp surged 18 percent after the company raised an operating profit forecast to 41 billion yen from 37 billion yen for the year through March. It also said it would buy back up to 900 million shares, or 4.6 percent of its shares outstanding, which is worth up to 20 billion yen. The company also raised year-end dividend payouts.
The broader Topix dropped 1.3 percent to 1,370.32 and the JPX-Nikkei Index 400 shed 1.3 percent to 12,366.64. (Editing by Simon Cameron-Moore)