Thinking about this now - it sounds as though you don't have enough fuel in the carbs. Fuel only trickles through to the carbs when the engine is being started, the carb bowls must fill up with fuel before the bike can be started (this can take a long time if you've drained the carbs).

Take the vacuum hose off the fuel tap, replace it with a different piece of same sized hose (car washer hose from an auto store perhaps) and suck on the other end of it - this should fill the carb bowls with fuel after a minute or so (carbs will overflow if you leave it too long, no big deal). Obviously make sure your tank tap is turned to on or reserve (depending on fuel level) when you do this.

Once the carbs are full of fuel, replace the vacuum hose on the fuel tap and start the bike (use full choke, no throttle). If it cuts out after 8-10 seconds or when the carb bowls dry up you'll know that something else is up.

Sorted it!!

The problem was the carbs weren't properly mounted! Thanks for all your help, apologies for my brief levels of incompetence!!



Cheers,

Tom

Haha, at least it's sorted! My mate had the same issue once a few years ago when racing with bemsee, he was running a stock engine in the formula 400 (before they ran a 64bhp class) and just thought everyone elses bike was tuned that much more as we was getting peed on down the straights. He eventually got it dynoed and found it was only making 45bhp, turned out the front carbs weren't seated!