I own 2 140 fz's and am very happy with their performance running powermaster 20/20. Can you explain how changing a couple parts (L) can produce a significant power increase and yet a new fuel system (DZ) can further increase power? Doesn't this increase in power add up to more stress on the engine and reduce engine life?
Also... at what point should I dissassemble the engine and change bearings/piston/sleeve assuming the engine hasn't been abused?

The L has the crankcase sealed using a ring on the crank (like a 61 AR did). That and the compression ratio is changed a little over the FZ, but it created a motor that required a little more finesse in running.

The DZ is a new animal, the fuel is injected cold (never passes through the motor) directly into the head, I beleive that this is the main cause of the power gain. The DZ will essentially spin a 1" larger diameter prop at the same rpm as the L all other things being equal. The difference in the DZ is that it runs very cool in comparison, so hopefully it will wear less than the previous motors. The vibration has been reduced a lot so they must be going down the right path with it.

Yes you can get more stress on the motor with increase in power, but if properly designed this is not a problem, as the components are redesigned to accept the increased stress levels.

Generally I dont like to change parts unless it is required, if your motor is running good leave it alone. As a guideline if your motor has been ran properly you should get 20-25 gallons between servicing.

Chad Northeast
YS Sponsored Pilot