Okay here is a tester for you,
I have been working on my own quads for 10 years and I can't figure this one. I bought a 2004 DVX (same as a Suzuki LTZ 400) which had 10 hours on it. Looked new, started right up, ran for a few hours then started stuttering and stalling. Looked inside the carb and there was what looked like rust particles and residue. Apparently it was the original gas from new!

So, I have cleaned and rebuilt the carb. petcock and gas tank. It still runs and dies. I installed a fuel filter between the petcock and the carb and can see the fuel stop flowing. I switch it to prime, the bowl fills again, it runs until the fuel stops flowing then same thing. It is driving me crazy, does anyone have an idea why the fuel stops flowing to the carb?

Suggestions appreciated.

 

is your fuel tank vented? does it have holes or a hose and is it clear and unplugged? also flush your tank.

 

Did both of those to no luck

 

I have flushed the tank 4 times with Acetone, removed the petcock and inspected the tank. It is clean as a whistle. I disassembled the petcock and thoroughly cleaned it as well ( it was very dirty). I think i might have figured it out. I will be taking it for a test ride on thursday and will report back. When I cleaned the carb previously, I dropped the float and it fell apart. I think I might have put the plunger spring on backwards (180) when I reassembled it which made the spring susceptible to catching thereby keeping the plunger in the closed position when it bumped around. I flipped it the other way last night and it makes it harder for the spring to slip and catch on the end of the float piece. Let's hope that is it!

Will report back.