My friend will get his back friday, they told him they orderd the same pump that was on it, not a larger pump??? guess their thinkin it was a falulty pump instead of too small. i dont think thats the problem. his had already been rejetted and didn't help. he cant ride until this weekend so will know more then. i took my carburator apart last night just to make sure all the jets were what the manual showed, and they were. there in an adjusting screw behind a brass plug that wasn't pluged on the '04 models, not real sure what it does. i am tempted to drill out the plug and try adjusting, but worried about voiding warranty. the manual says "pilot screw 2 3/4 turn (taper12.5 deg)(brass plug).

 

They also gave her some bs about the atv only being tested on level ground when they were made. Sounds like it might be more than the jets, but we'll see when she rides it.

 

Same thing here.. They dropped the main down since the plug was jet black.. Still want to know if the fuel pumps are the same on the 400 and 500.. and why no problems on the pre-04 400? Was the pump changed? or maybe indeed it is a jetting issue. The saga continues!

Ron
04 Sportsman 400

 

I downloaded the parts books for the '04 & '04.5 400's. the only difference i see with the carburetor is the '04 had a 167.5 main and the '04.5 is 172.5. the pilot jets both say #40 but have different part #'s. Looks to me like a 167.5 main might be worth trying. The pumps have different assy. numbers but internal parts are the same.

 

The one thing I do not hear mentioned is wether or not you have the machine in low range. This is important because in high range with uninterrupted torque the clutches cannot backshift. What is happening is the tires are spinning allowing the clutches to upshift. Then you obtain traction and the clutches have not backshifted yet. Some of you claim if you let off and get back on the throttle it corrects itself momentarily. Again! this allows clutches to upshift, this is when you should stop, shift into low range, then continue.
I know how chat rooms work. When someone posts a problem and somebody offers a solution it is often rejected because people want their problem to be "SPECIAL". So before you respond remember profesionals are probably viewing this and need honest feedback to fix the problem.

Thank you.
Phattpatt

 

Low range makes no difference..

Ron
04 Sportsman 400

 

Phattpatt ,

mine will do it in either low or high, what you say about the clutch makes sense. i almost always climb in low range, the loss of power and missing "feels" like carburation. i am going to try the smaller jet in mine this weekend and see what happens.

 

I just found out this info from a reliable source. Go to a 162.5 main jet and re-adjust pilot.

 

Now wait a minute, you cant just tell someone to go to a 162.5 main and fix their problem.
Remember that jetting reflects altitudes effect on the fuel/air mixture. What jetting may work for me at 1000 feet isnt going to work for someone else at 7000 feet.
Safest wahy to rejett the main is to go down one step at a time and watch your plug.. I think we are getting on the right track here though.

Ron
04 sportsman 400
Heelclicker
GPS

 

ktmguy,

You have somewhat of a point. But remember this is not a two stroke. Also for the majority of people out there 7000 feet is probably a little extreme. Refer to your owners manual for jetting ranges. The info I gave is definately ok for 0-3000 feet