98 hawk stutter/stall
 

98 superhawk studder/stall - YouTube

If you hold the throttle at a steady rpm it slowly drops then stalls. we have cleaned/rebuilt the carbs, synchronized, new stator, new r/r, swapped to 01 CBR coil pack, new plugs, new air filter/those little sup filters, and a new battery. After all that it has gotten worse and is now doing what it shows in the video on the stand it started sporadically doing this at red lights a few weeks ago and now its every time you start the bike up. Hope some one can help me at a loss.

How does the petcock look? Is the vacuum line to it in the proper position?
It does sound like it is running out of fuel.

the petcock is set all the way open and I'm 90% on the right vacuum line position but it is late here and i don't think the neighbors would like the messing with it any more for the day. I will double check them when i wake up. is there any thing else i could check if that's in order.

+1 mine did this when petcock went bad fuel was dripping from the tube that points down...

Well you only need 3 things for the engine to run.

Spark

Compression

Fuel

The first 2 sound like they are there as the bike starts

Which would leave a fuel problem.

So first make sure the fuel is flowing. Which would be the petcock actually opens and is hooked up properly (vacuum line to the fitting on the side, not the bottom) and the internal filter is not clogged.

If the petcock doesn't leak, I would then put vacuum to the fitting (use something like a mity-vac or just hook a line up to it and suck on the hose) and check to make sure that fuel flows from both outlets.

If that is all good, check the float vales and the floats. Make sure everything moves freely and doesn't stick.

I would bet you problem is one of those two things.

Also, check the condition of the vacuum line running to the petcock. If it is letting air into the engine then the petcock will not operate properly. Old vacuum hoses can and will cause problems.

does it do it with the fuel filler cap open? vent hole could be clogged.

as of now it is fixed. worked on it a little to long yesterday and had the vacuum lines hooked up backwards. and as far as the original problem of doing it randomly at stop lights it seams to have bin fix by synchronizing and swapping over to the 01 CBR coil packs. thank you all for your help you guys are very knowledgeable.