Hi, I have a 1988 k100, with 35000 miles on the clock. It starts fine and pulls well through all the gears with no hesitation and plenty of power, but when I get to around 4000 rpm it struggles to rev past and will not go much faster. Any Ideas where to start? This is my first K100.
Cheers
Ben

very difficult to tell you what could cause the problem.
Have you started with the basic: new set of spark plugs, clean air filter, fuel filter (the bike may be starving for fuel)
What is the color of the spark plugs? are they all the same?
Just give us some details of what you already checked and when the last major maintenance has been done (oil, filters,....)

Hi, thanks for your reply. I have replaced the plugs already. Having only recently purchased the bike I Dont know when it was last serviced properly. The guy I bought it off should be back to work this week so I will confirm. I will change the fuel and air filter anyway as a matter of course.
Cheers
Ben

How did the plugs look?