[AshG]

contrary to popular belief you shouldn’t need to rejet them. when they set mine up at ATSPEED they just re-profiled the needles.
a good tuning place will allways try and re-profile the needes before they re-jet.

you have to be very careful when rejetting as it can mess up the low rpm fuel economy.

basically the needles sit down in the jets and as the revs rise the needles lift up out of the jet hole letting more fuel out. so if its fuelling correctly at low revs but under fuelling at high rpm you just make the bottom of the needle thinner to increase the fuel. you should only rejet if the needles are all the way out of the jet and its still under fuelling