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.

 

Om my 96 454 4x4 there is a fuel filter under the sleeve for the fuel needle valve. Took me a good bit to find it. A single screw holds the sleeve in. Remove screw, slide sleeve out and filter sits right there. On mine the filter was 95% blocked so when it sits the bowl fills. After running a minute or 2 would use the fuel in the bowl and die out. Actually had to clean mine twice about 6 months apart. The extra fuel filter may keep "stuff" from getting to that filter after you clean it. Should add in line filter to mine. Lots easier to get to. Hope this helps.

 

Not my area of expertise, but have u tried with the fuel cap off? Possibly might be getting a vacume and not allowing the fuel to flow properly.