Tired old zzr250 which I only still have because I can't currently afford an upgrade. While riding to a friends, no obvious issues with the running of the bike, I took off from the lights without as normal and caught up with the traffic and suddenly the power output from the engine went to about 1/3 of the normal output. I pulled over and looked over the bike, not sure what I expected to see, but everything sounded fine, and the revs sounded smooth. It just wasn't converting that noise into power. My initial thought was that there was a spark issue, so I pedaled the bike (well, rode it at pedal pace) to my friends where I pulled off the tank & checked the plugs. Both exhaust pipes were hot, and the plugs looked fine so, nothing obvious there. I had to get the bike home, so rode it in it's current state a total of about 25-30kms with no change. I've checked the fuel lines, and they are all straight without kinks, the inline filter, which has always been there, was clean and about 80% full of fuel. So it seems fuel is getting _to_ the carby without issues, Though I didn't try turning the choke on while riding it to see if it wasn't getting the fuel it needed If it was water in the tank, I would have thought that would have had a more dramatic affect (coughing & spluttering). I'm assuming that I'll have to pull the carby off & clean whatever gunk has accumulated there. I'm capable with a spanner, but no mechanic, so any ideas / tips?