Please Help Sick 300ex

Hey guys my nephew has a 300ex and he needs some help.
Every time he pulls the front tires up to wheelie or tries to climb a steep hill his quad cuts out really bad or just dies. We checked the air box, cleaned the filter, changed the plug, changed the fuel , and his dad checked the carb. Any ideas would be greatly appreciated. We got a big day of riding tomorrow and it will just kill him if he can't ride.

Thanks

Chris Medsker

[51]

hm..kinda a wierd problem nevr ran into this vberfoe is his intake clean is his acclerator pump bent or maybe not squirting hard enoung ( not exact terminology but thats how it came out???? )
have you check his ground? maybe it wiggles loose or something..i can't really think of anything but i'd look over evrything good

The weird thing is that it runs perfect other than hills and wheelies. It makes me think there is somthing in the tank or carb but if there is we can't find it. We drained the tank and checked the bowl on the carb they were both clean???

[51]

is his jet still in there ? and tight? and it his lil hose thng that runs from the tank to the car clean?

My brother -in-law said he checked the jet and I checked the overflow. They took it to a mudathon last week and thats when it started.

[note to self don't do mudathons]

[Leo]

check the float height in the carb...

also check all the carb drain/vent tubes to make sure that one of them isn't plugged up with dirt.

Leo

Thanks for the help guys we will give that stuff a try tomorrow.
Checking the float height may be a little over my head though.