SRV250 oil leak from bottom gasket

I have a 1998 SRV250 Renaissa,with 33,000km on the clock. I've had 20,000 trouble free kilometres out of the bike (except for replacing a starter motor because the sprag clutch collapsed). The bike has been weeping oil from the gaskets at the base of the barrels, for about the last 3,000km.

A freind, who used to be a BMW mechanic, suggested that a re-tension of the head bolts may help. It means removing the motor from the frame and putting the torque wrench on the head bolts. Any idea of the torque setting for these head bolts? Fraser Motorcycles mechanic suggested that this wouldn't work and estimated the cost of replacing the gaskets at between $500 and $600 - that's with me taking the engine out of the bike! Sounded a bit steep to me.

The only other problem that I have had with the bike is with the speedo. The needle has a mind of its own. I can do 120kph pushing the bike up the driveway! Fortunately the odometer is direct drive and works well. I tried to buy a second hand speedo at Joes Wreckers, in Fyshwick, without luck. They could supply a new one for $350, but the bloke did say that all Yamaha speedos are geared the same, so I may be able to get a speedo from another Yamaha. Any thoughts on that?

Thanks

Travers