Strange random power loss mainly at wot

[Broken Boards Skateshop]

I just picked up a 91 400 that had not been ridden in a few months I probley should have just drained out the old gas and gone from there but I road it as it was I was to excited.  The problem is sometimes when I am riding it it will start to cut out then kind of kick back in over and over again (kinda sounds similar to a rev limiter sound but at random rpms usualy at wot).  After I refilled the tank with new gas it seems to happen alot less often and pass more quickly.  When I filled up today I noticed just a tiny bit of crud in the tank and am wondering if maybe the fuel filter or petcock might be clogged or something cutting off fuel if that makes any sence.

[PitterB4]

A clogged fuel filter could certainly be the culprit.  Could also be a blocked or kinked vent line from the tank.  When it "cuts out", does it just lose power, completely die or does it sound kinda like a tractor?  If it's that tractor sound, it might be loose connections to one of the coils (dropping you to two cylinders).  Mine did this.  Last question...  is this kicking tied to hitting bumps?  My ZX did this and it ended up being a loose battery connection.  It would shake loose momentarily over high speed bumps and kick like a bronco. 

[pmackie]

In addition to Pitter's comments, I'd start down this path:

1. Clean the tank
2. Change/Install a good fuel filter
3. Change the air filter
4. Clean the carbs, checking for wear
5. Sync the carbs
6. Check the plugs, caps & coil connections

[Broken Boards Skateshop]

I cleaned out the tank as good as I could and blew some air through the petcock and it seems to have realy helped.  The bike kind of studdered once when I first took it out other then that seems to run good now.  I will probley get into cleaning the carbs and syncing when I get some rain in the forcast.  Thanks for the help