250exridr
NH/MA
Elite Member
Joined: 08/23/2005
View Profile
 Offline
|
ok this problem has been plaguing my 400 for quite some time now and i am turning to the forum for ideas because I dont know what is wrong with this thing. At the beginning of the summer I tried getting it going and it needed a carb rebuild. My mechanic rebuilt the carb and I took it riding up in VT. It ran fine until towards the end of the trip. It will run good for about 20 min and then when it starts to get hot it will sputter, bog down, bad low rpm throttle response, and dies at idle. The carb is not dirty. It was rebuilt and then cleaned again. My mechanic gave it back to me and told me he's tried everything and can't figure out what is wrong with it. He called other mechanics at surrounding dealerships and they said it sounded like the carb was dirty but it isnt. Now a friend of my moms is looking at it since he's had them his whole life and knows some people at a dealership so maybe they will be able to get it fixed.. Any ideas what could be wrong with it?
02 400ex with modZ
|
WoodsRuner
Ashille, Ohio
Elite Member
Joined: 11/08/2003
View Profile
|
The fuel strainer in the gas tank is dirty.
03 Rincon 650FA w/mods
03 Rancher 350TM w/mods
Calling a illegal immigrant an "undocumented worker" is like calling a drug dealer an "unlicensed pharmicist". Both are criminals!
|
Magnum Eagle
Ridgecrest, Ca
Senior Member
Joined: 04/17/2005
View Profile
Offline
|
250exridr,
I agree with WoodsRuner. If you had to clean the carburetor at the beginning of the season chances are the problem is in the fuel supply. Contaminated fuel probably caused the carb problem to begin with. There may be sediment in the strainer or in the tank. Let us know what you find.
Sid
|
cchagros
New Hampshire
Moderator
Joined: 02/23/2005
View Profile
Offline
|
Justin, if you let it cool down, does it run fine again until it gets hot again?
2010 Honda Rincon, Red, Bone Stock
2005 Suzuki King Quad, Yellow, Mudlite XTRs
|
250exridr
NH/MA
Elite Member
Joined: 08/23/2005
View Profile
Offline
|
Magnum Eagle wrote:250exridr,
I agree with WoodsRuner. If you had to clean the carburetor at the beginning of the season chances are the problem is in the fuel supply. Contaminated fuel probably caused the carb problem to begin with. There may be sediment in the strainer or in the tank. Let us know what you find.
Sid
If this is the case why wouldn't it happen all the time instead of only when the engine has been fully warmed up?
|
WoodsRuner
Ashille, Ohio
Elite Member
Joined: 11/08/2003
View Profile
|
VACUUM! As the fuel is removed from the tank, the crude plugs the strainer tighter and tighter, until finally there is no flow or very little flow. Turn it off to cool and the crude loosens, allowing fuel flow for a while.
Might want to check the vent in the fuel tank cap as well, And make sure the vent hose is not plugged up. A plugged vent or hose will let it run for 5-10 minutes, then the fuel stops, since the vacuum on the tank is greater than gravity pressure.
Might be vapor lock as well.
|
