[Sra.MooN]

Hello all, new to forums.
I am writing in regards to a problem I am having with my dirtbike. I live at an elevation of 5300 feet and am wondering what size jet I should use. The stock is a 160. 160 had always worked fine at this elevation and higher elevations. A couple weeks ago I was up in the mountains and my dirtbike would foul out at wide open throttle. It would not die completely. If I turn the gas if it will run fine until it runs out. Anyone know why this is happening. I fired it up where I live at 5300 and it does the same thing it will run fine but as soon as I give it full throttle it just dies out. I can turn the gas off and it will run perfect until the gas in the line and bowl is used. I checked my petcock and it works perfect. Pulled the bowl off of the carb and the floats are working fine. Any help would be greatly appreciated.

 

[ZX-2R]

CHECK

First thing to try is new plugs...This has been a problem in the past on many occasions...also check your air filter and your airfilter box. If this is fine then wait till dark and take out a bottle of lightly soapy water and use a misting spray to see if perhaps the spark plug boots or wires are sparking and just keep spraying things till you find the problem area...it could many things at 5300ft. I suspect you will find it to be electrical and not fuel related unless you have changed fuel and it isn't as good as it should be...try running some fresh gas preferably Premium in it...is your automatic oiler adjusted right? or do you mix it yourself??? check that it is actually working when you twist the throttle an dthat you haven't changed the type of oil. Injector oil is different...and it is pretty picky if you put in the wrong oil or even change brands...

 

[Sra.MooN]

when i turn my gas off my bike runs fine...this is why i think it has to do something with fuel.

 

[Tart]

hiya,
check the breather in the fuel cap and the little pipe coming out of it isnt blocked or kinked, sounds stupid but it could be causing a vacum in the tank and its sucking fuel and air up from the carbs, and thats why the engine runs ok when you shut the fuel tap off.

just an idea.