Total Motorcycle Community Forums

83 cb650sc nighthawk. Rebuilt carbs, new cam chain, new air filter, oil and filter. Decreased fuel milage. Not that much of a change but enough to be noticable.Used to get 200 klicks or better per tank, now getting 175klicks. Have some fluctuation in the idle adjustment; set the idle at low starting temp(or the bike starts but won't idle, gotta leave the choke on ) have to re-adjust when warm or the idle is to high. Otherwise the bike is running really well. Any ideas on what to look for or adjust.

wrong size jest eg main jet shoukld be .1xx, but the shop fitted the largest optional one, as that is what they had. A change from a .112 to a .108 makes a huge change. Don't know if the CB650 carbs had a needle that could have its position changed?
Soft tires, dragging brake, even VERY slightly, bad wheel bearings, clogged air filter (wash and oil, or a new one)

Did you do the carbs yourself?