Motorcycle Repair: Im loosing mojo, fuel delivery system, full throtle

Question
I have: 2004 shadow 600vlx (10,000 miles)the bike is basically turning off only when I'm at full throtle at about (60-80mph.) on 4th gear ofcourse. I can continue all day long with no problem as long as I don't apply full throtle ( throtle about half way is okay). as a matter of fact the bike has good take off power on 1st,2nd and 3rd gear. I've done the simple basics checked plugs, air filter, cleaned carb with spray, checked stand switch, disconected the carbon filled emisions canister...any help sir or ideas i would apreciate.

Answer
Robbie, you didn't mention if you have done any mods to the bike like air filter and/or exhaust changes that can affect WOT performance.

If the problem exists in all gears at the same throttle settings, then the problem is most likely in the fuel delivery system. I don't know if "cleaned carb with spray" meant removal and disassembly of the whole carb or just cleaning out the float bowl. There are emulsion tubes in the carb that may be blocked where they are cross-drilled to allow a favorable mix of air/fuel before it is drawn into the intake manifold.

http://www.houseofmotorcycles.com/fiche_section_detail.asp?section=174760&catego  #19

Modern gas doesn't last long without stabilizers and separates into layers of alcohol and gasoline, both in the fuel tank and in the float bowl. If there is any doubt about the fuel quality, drain and refill with fresh fuel. You may have refilled the cleaned carb with separated gasoline.

If there are any mods to the intake/exhaust system you will need to increase the main jet size one or two steps.

Fuel flow can be impeded by clogged fuel screen on the petcock (inside the fuel tank), the fuel filter & low-flowing fuel pump. If the fuel tank isn't venting properly, the fuel flow will be restricted, as well.

Read the spark plugs, looking for signs of either too rich or too lean on the plug tips and insulators. Try adding a little choke to the engine when it hits the point of stalling out. If it perks up, then the engine is too lean. If it chokes down worse, then it is too rich.

Bill Silver