I am currently running a well maintained 1974 R75 /6. Over the past several years I’ve changed out or replaced most if not all of the common troubled areas dealing with this motocycle, but I am still am having a power (horsepower) issue. It periodically feels sluggish and while riding at highway speeds I lose power and either I need to downshift to maintain speed or sometimes adjusting the choke helps maintain speed (but never increases it). Furth more, I have never been able to pull more than 5,600 RPMs on the engine since I bought it. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o> Here is a list of a few things I have done already: <o></o> New plugs, always 93 octane fuel, new battery, switched to an electric ignition, changed the diode board, cylinder compression seems fairly good (not sure what the standard should be), oil changed regularly, valves adjusted at every oil change, cleaned the carbs and checked the internals (everything seems fine), replaced the ignition coils. <o></o> Is there something else I am missing / should check, or is issue sound more like an engine internals (valves, pistons,… problem?