Originally Posted by TripTheNinja
- Top end power struggles from 70-75mph. Could still need some fine tuning
There is no reason a well tuned DR/bst40 should not accelerate cleanly and fairly briskly to an indicated (stock speedo) 95 or even 100mph. It does start to flatten out around 90, but should still be moving up. Mine did it when stock at 4500'asl. Does it even better with some carb mods and improved gearing (14/43), and I weigh about 200lbs in my riding gear. I would look to fine tune the jetting a little more. Taping off the airbox some can give you an indication if you are lean or rich (if it runs better you are lean, worse you're rich).