* Upbeat U.S. private payroll data boosts dollar
* Yen hampered by Japan's trade deficit, economic woes
* Break of 80.60-65 could signal bull trend for dollar/yen
* Euro lower after Greek court ruling on austerity steps
LONDON, Nov 2 (Reuters) - The dollar rose to a near four month-high against the yen on Friday as investors bet on an upbeat U.S. payrolls report after private employers added jobs at the fastest pace in eight months.
The euro eased towards a three-week low against the dollar after a Greek court ruled the pension reform demanded by foreign lenders may be unconstitutional, raising concerns about Athens's ability to implement the austerity measures needed to secure bailout money.
All of which saw the dollar index rise 0.25 percent to 80.25, breaking above its 55-day moving average of 80.14 and trading not far from a seven-week high of 80.325.
The dollar was up 0.2 percent on the day at 80.35 yen, just shy of last week's four-month high of 80.38. Traders reported an option barrier at 80.50 yen with hedge funds seeking to buy the dollar at dips in case the U.S. jobs numbers disappointed.
A break of resistance at 80.60-65, a chart triple top marked between May and June and a 50 percent retracement of its March to September decline, could signal further gains.
``A good U.S. jobs number will no doubt give a leg up to dollar/yen,'' said John Hardy, currency strategist at Saxo Bank.
``From a medium-term view, we are bullish on dollar/yen and the pair has established a base around 79 yen for a rally to 88 yen in a year's time,'' he added.
The yen has come under pressure because recent Japanese data and corporate earnings have been soft. Third-quarter economic output data, due on Nov. 11, is also likely to have contracted.
``The Japanese electronics industry is collapsing. Auto exports to China will be falling sharply. So Japanese exporters' dollar selling will be dwindling... There's no reason to be bullish on the yen,'' said a trader at a Japanese brokerage.
By contrast, recent U.S. data have pointed to a recovery. Payrolls processor Automatic Data Processing said private employers added 158,000 workers last month, bolstering expectations that the non-farm payrolls report due at 1230 GMT may beat forecasts.
A Reuters poll showed analysts expect a rise of 125,000 U.S. non-farm payrolls in October. The unemployment rate is seen ticking up to 7.9 percent.
Any market reaction to the jobs data may be short-lived given the uncertainty of the outcome of the Nov. 6 U.S. presidential election.
EURO IN A RANGE
The euro was down 0.3 percent at $1.2900, as traders sold the currency with the aim of triggering an option barrier at 1.2880. Bids from Asian central banks and Middle East investors were cited below $1.2880.
However, it held within the $1.2800-3200 range seen since September, underpinned by the European Central Bank's pledge to buy bonds of indebted euro zone countries that seek aid.
Signals in the option market showed the pair was likely to trade in a range in coming weeks. The one-month implied volatility on euro/dollar options fell to fresh five-year lows around 7.50 percent.
Data on Friday showed the peripheral euro zone countries were still struggling. Spain's manufacturing sector shrank last month at it fastest pace since July, while Italian factory shrank in October for the 15th month running.
Commodity currencies eased after rallying earlier in the day. The Australian dollar hit a five-week high of $1.0420 before giving up gains to stand at $1.0383. It also matched its August peak of 83.55 yen.
The currency was helped by Thursday's improvement in manufacturing data from China, Australia's main export market.