Motorcycle Repair: 1979 Honda CB650, kawasaki vulcan 1600, honda cb 650

Question
y Bill;

A little help here.  I have a '79 Honda CB 650.  Bought it from a friend last fall.  It had been stored (inside) for 11 years.  It has fewer than 14K on it. Yeah, it needed lots of help.  Among other things, carbs were off several times.  Parts cleaned and some parts replaced.  Carbs were synchronized.  Bike starts and runs quite well.  However, at ~5000 rpm acceleration/power becomes noticeably flat.  What could be the problem?
Both this Honda and my '05 Kawasaki Vulcan 1600 Meanstreak get around 40 mpg.  Is this about what I can expect from the Honda?  

Answer
Ken, your flat 650 problem could be due to several sources. First of all, the battery needs to be fresh and able to pass a load test with flying colors. Then, you need to check the charging system output... these bikes have a history of bad alternator rotors, stator and reg-rectifier problems. Make sure that the stator wiring harness connector is clean and tight.

Did you pull the petcock off the tank? The whole fuel system needs checking and cleaning. There is a fuel screen inside the fuel tank on the end of the petcock. Might be clogged and/or passageways inside the petcock could be blocked or restricted.

If the bike has stock air filter and exhaust, then the jetting should be okay. If any changes were made do the intake/exhaust system then the carbs may need rejetting.

CB650s should get mid-40's mpg on average.

Bill Silver