I agree with bigbob and gtsmrt. This classic Tiger problem is likely to be fuel percolation caused by heat soak. When the engine is stopped after a decent run, coolant is no longer being circulated through the block, heads and radiator. The heat builds up and is transferred to the inlet manifold and carburettor body and fuel bowls.
There are several things you can try.
First, buy and install as thick a phenolic spacer as possible (½, ¾, 1 inch) which will still allow you to close the bonnet on the air cleaner. This should drop the temperature of the carburettor body considerably. Touch the carburettor body before and after fitting the spacer and feel the difference.
http://www.summitracing.com/search/Part ... lic+spacer
Second, if possible after a run, open the bonnet to allow some of the heat to escape. Running electric fans may help a little but there is no substitute for pumped coolant circulation.
Third, fit a transparent inline fuel filter (5/16 or 3/8 inch fittings) similar to this:
http://www.summitracing.com/parts/TRD-9245/
This will let you see if the fuel is bubbling due to the fuel pipes getting hot. The fuel pipes near the engine/exhaust can be insulated by splitting a suitable piece of rubber hose.
As per bigbob's suggestion, also check all your electrical connections and the state of your battery.