Last week I left my 1990 yamaha FZX250 (commuting bike) with a mechanic for a full service + carburetter to be tuned. I've got it back, now it doesn't accelerate up hill properly - hits 6-8krpm (if that) and flattens out even in lower gears. Then If I try to drop down gears, it stalls as soon as I pull the clutch in. It no longer takes corners uphill happily either. As soon as there is any load it seems to struggle maintaining speed. I seem to be operating the throttle flat out where I didn't before. The other thing I noticed is that sometimes the idling sound appears to pulsate - with the occasional rapid jump in speed. I run the bike on premium fuel if that makes any difference. Can anyone suggest what is wrong? has the carburetter been setup incorrectly? or is the fuel pump failing? everything else seems fine. Would greatly appreciate any thoughts on what has changed before I ring them up and complain.