looking for ideas??

[tub350]

hey guys, sorry but i think i have another jetting question for ya...

i have an 01 ec250, top end rebuilt around 800kms ago, v-force reed block and LTR power valve cover fitted, carb still has the original jets N1ed needle no7 slide air screw 1.5turns out. bike starts ok from cold and 1st kick when warm, splutters a bit from idle to 1/4 throttle after a bit of slow technicle stuff but generaly runs fine, always has a little trail of splooge at muffler tip.

Now to the problem,
on open hi way sections of tar (10kms between home and forrestry) between 90-110km/h going from 1/8 throttle to 3/4 or wot it just dies as if running out of fuel.. i thought it was running lean (hot) but engine and radiators not excessivly hot and no detionation rattle, then thought vapor lock and opened up the hole in the fuel cap, the anoying thing about it is once i turn off the main road back to dirt it will go from idle straight to wot without hesitation.

sorry for the story but any help and ideas are welcome