First off I have learned that I am too vague so I will try to be as detailed as possible. My bike shows as being built 8/70 but registered as a 71 CB450. I had found that I had a cracked float on the left side carb. I have been having some trouble with the carbs but it was only sporatic. The problem is this. The right side exhaust is running pretty cold as well as getting some backfire through the exhaust. None through the carb. I static timed it per instructions here. I then checked the timing strobe style. The timing at 1,100 rpm is spot on on both sides. When I try to check it at 4,000 it is slightly retarded. I have the 14H carbs and am running a 130 main, and 38 pilot as well as low speed. Air screw is just over 3/4 out. Compression is 168 on the right cylinder and 161 on the left with the throttle open. Coils are new as are the points and condensor. I am also getting good spark on both cylinders. I really can't tell you if carbs are truly synced since I have an exhaust leak on the left pipe but intake pressure seems to be the same. So my question is what could cause the right cylinder gas to be coming out cold but seems to be running strong at idle. How to correct/what's causing backfire through right cylinder? do I need to adjust the timing for 4,000 rpm and if so then does that involve bending the tabs? Oh yeah gap is within specs. Should I maybe decrease the float height on the right side? (They are both at 20mm) I just cleaned out the carbs last week in case of rust and I am going to seal the tank next week. I also did the straw test and they both passed. Intake boots are in great shape with no visible cracks. Thanks for any help.