fuel line problems

Here is the deal, I have a 06' CRF450X street legal supermoto. When I am running down the road at 5,000 rpms the fuel line starts to run dry. (clear fuel tube)

I have checked the fuel filter and even removed it! All the carb vents are not clogged (blown out with air) the float is set correctly (10mm like it says in the book) The petcock is free from debris. The fuel line just seems like it is becoming "air locked". It will do this even with the gas cap removed! And when I return to idle is takes forever for the line to re-fill (if the carb does not run dry first!)


I noticed when I ride off road (rough terrain, on and off the throttle) the problem does not occour

did you alter the float level?

I set it at 10mm when the needle contacts the seat. (not when the needle spring bottoms out)

You may want to pull the needle seat. Some of them have strainers, you may have a clogged one

how far was it off?

It was not far off at all, I checked it when I cleaned the carb, checked the tune up and serviced air filter.

did it do this before you adjusted the float level?

I figured it out, I removed the fuel valve and ran a line straight from the tank to the carb and no more problems. I am going to build a mount for a ball valve to use as a fuel cut-off.

I took apart the fuel valve (stock) and it's no wonder enough fuel can't folw through there the valve is a pancake or as I like to call it a "smiley face" design. It just can't keep up with the demand of 1/2 throttle for 5 min. on the street. I don't know if the R models have this problem because it is a different valve (no reserve) possibly the orfices are bigger.


was there a rubber washer in between the valve and the body?? maybe the washer was turning with the valve as you opened or closed it?

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