85 vf500 falls flat at 6000rpm

Got my 85 vf500 running carbs are synced and it runs great but is really down on power and only pulls to 6000rpm. I havent reset the pilot screws yet could this be the reason or should I pull the carbs and change the setting on the needles? any other ideas? I checked the timing and its dead on. I've also already adjusted the valves

 

Have the cams been out? They could have been put in 180 degrees out of phase.

 

sounds like the vacuum on the petcock isnt hooked up. check that out

 

WHAT it is is: probably sticky throttle slides or torn, leaky diaphrams is what that is......

make a compression test.

IF u think pilot screws have anything to do with this, start reading up, man!

 

New plugs and wires. Or possible bad coil/ignition box. If the wires are original after 23 years you should replace them. You can make your own w/7mm wire. Pilot screws are not used that high in the rpm band.

 

what wasn't was that ^^^^^

what it was was the petcock didn't have sufficient vacuum running to it so it wasn't opening all the way thus starving it of fuel. nothing to do with the carbs

oh I also already replaced the plugs and wires. bike runs amazing now after now running for 9 years

 

Good find. Glad you got it fixed easily.