flw wrote:One of the things he told me is that a Inline parellel engines do not generate the rpms/HP that a v twin can in a sport configuration.
Now if you're only talking about the difference between a parallel twin and a v-twin then yes, the guy at the dealership, and High_Side are correct. A Parallel twin (650R) requires a bit more balancing than a V-twin (SV650) and thus will not quite put out the same kind of power, all other things being equal.
If you're talking inline 4 cylinders vs v-twins, then the guy at the dealership is incorrect... it's the other way around. Inline 4's may produce less torque, but more horsepower because they're able to spin at much higher RPM's.
Horsepower is basically a function of Torque over Time (or in the case of an engine, RPM.) In general, the faster you can make an engine spin, the more horsepower it can produce.
Just about any modern Inline 4 cylinder 600cc engine will be able to spin 14-16,000 RPM's and put out anywhere between 90 and 110hp to the rear tire.
A Suzuki SV650 or Kawi 650R in comparison, can only spin to about 10,000 RPM's and can only put out about 65-70hp to the rear wheel despite having about a 50cc advantage, but is able to produce a comparable amount of torque at a lower RPM than your typical 600.