I have a 2001 DWG with a 42mm Mikuni carb and it started running rough and when I turned the throttle it hesitated so I disassembled the carb and cleaned it out real well with compressed air. I installed a rebuild kit with a new accelerator pump and all gaskets. When I start it up it runs fine for about thirty seconds then it starts to run rough and acts like it's running out of fuel. I checked the fuel filter and it is clean. I can start it up and give it a little throttle to keep it running then with the throttle position at the same setting it will act like it is running out of fuel then start running normal again. I know it acts like a clogged fuel filter or line but it's not what else could make it run like this?
Thanks.
Jeff

 

Have you checked your intake manifold gaskets?

 

 

Make sure your gas cap is properly vented also.
Scott

 

I vote on the vacuum operated petcock, but other suggestions should also be checked.

 

 

Disassembly and blowing out with compressed air could have dislodged some varnish blocking the float needle.