Motorcycle Repair: problem with gsx250e, gears inc, fuel hoses

Question
Hi Mark,
I own a 1981 suzuki gsx250e, The bike hadnt been ridden for a little while (6 months) due to a broken cdi. Just before it gave up the ghost the engine was reconed and electrical replaced... New cdi 1 month ago and everything been running fine for the last couple of weeks... couple days ago mabey 1km into trip and it starts losing power.
5000rpm in first gear and mabey 5km/hr if im lucky... let it cool down for 15mins and then fine for another 1km... since then nothing but the same. Happens in all gears inc Neutral and have noticed mainly after engine warms up.. can  rev it up for a minute or two and then suddenly loses all go. no smoke that i noticed and seems to change from power to no power intermittently ? ?
Please help.. ?   
To rich mabey ?

Answer
Hi Adam,

I suspect the engine is starving for air or starving for fuel.

Check air intake for possible restrictions.

Check fuel tank vents, carburetor vents, and crankcase vents.

Check for pinched, folded, or collasped vacuum and fuel hoses.

Respectfully,
Mark Shively