Motorcycle Repair: Very Little Vacuum On One Cylinder, honda cb400t, right cylinder

Question
Hi,
 I am working on my dads 1979 Honda CB400T Hawk. It has been running poorly. You needed to run with the choke full on until the bike was warmed up.So I figured the carbs needed to be cleaned. I took them apart cleaned them and put them back on the bike. Upon start up the bike does not run any better. So I tried to balance the carbs out. When I installed the vacuum gauges I see the right cylinder has almost no vacuum and the left bank holds about 15 inches of vacuum.I tried to adjust them with no results. Then I noticed that the right exhaust pipe is almost ready to turn red. I took the carbs back off and can not see anything wrong. Can you please give me an idea what to look for?

Thanks,
Gary

Answer
Gary, the carb with the low vacuum has the throttle plate open a lot more which is why the pipe are so hot.  You may want to check compression on the left cylinder to see if it's healthy. YOu may want to spray some water on the left cyclinder to see if it's firing normally. The water should sizzle on the pipes after just a few minutes of running.   I'm guessing the carb balance screws are too far out of adjustment.  Put a window fan in front of the engine to try and keep it cool while you try this.  Increase the idle speed to about 1500 rpm and then try rebalancing the carbs.  You will want to adjust them so as to close the right throttle plate and open the left.  

Regards
Rich