Motorcycle Repair: Idles fine breaksdown under load, suzuki gsx 250, crankcase blowby

Question
I have a 1998 Suzuki GSX 250 Across with approx 36k km on clock. It starts perfect first time and idles fine. (I keep it regulary serviced with one due now) When I take off slowly its okay but when I hit 4000rpm, theres just no power, no matter how far I turn the throttle. It glugs along like it either is not getting enough petrol or to much. There is no backfiring but it feels like it wants to. The Bike was recently loaded onto a truck while moving and found out that they nearly vertically lifted it onto the tray. I found in the filter box a mixture of Oil and Fuel. I cleaned it out but still no change in performance. I haven't inspected the spark plugs yet or drained the fuel tank to check for signs of water? It has only just happened over the last few days and I have a feeling that when they lifted the bike nearly vertical it may have done something (If thats possible) displacing something in the carbies or somethings mixed together that shouldn't have. I thought it may have been the CAM belt adjuster but I can't hear any "Clunking Noises" I recently put petrol in the tank and may suspect water.Any Suggestions would be appreciated

Answer
Craig, I don't have any info on your bike, but if it has a paper air filter that was contaminated with oil/fuel, then it needs replacing. If it is a washable foam, then have it serviced. The air box has separation systems to take out the moisture, fuel vapors and crankcase blowby solids where they can be drained periodically. Check your owner's manual for details. Its all part of the emission control system.

If the filter appears okay, then just replace the spark plug next. Running the bike with the sludge in the air box or air filter may have just fouled the plug.

If that doesn't fix it, then perhaps there was some water/dirt, etc. in the float bowl that got dislodged when the bike did its involuntary wheelie and has settled into the main jet. You can try to drain the float bowl with the drain screw/bolt at the bottom of the bowl. If the bike has a vacuum petcock, it may take awhile to get it started again with an empty float bowl, however. You may have to have someone remove the bowl and check the main jet for clogging.

If the petcock (fuel valve) has a screen or sediment bowl, clean that out, too.

Debris or contaminants in the fuel tank could have been dislodged, too and floated around to block fuel passages somewhere along the line.

Bill Silver