my friend has a 2001 400 scrambler with hot seat performance pipe and silencer and clutch kit and has a k+n witha ported cylinder and a wiseco piston.he is running a 300 main and a 25 pilot jet.3 different polaris gurus has worked on this beast with no help.if you stop on a any little hill and try to pull back out it will miss and sputter and barely move even at full throttle.on level it will sputter untill it rolls about 30 feet and then it runs excellent.what could possibly cause this?if this cant be solved he is going back stock.

 

Sounds like a problem......

1st thought: Fuel, does this happen on flat ground as well as a hill? I would clean the carb, & check the jetting. If all this seems right and it's not a fuel circut, then I would start looking else wheres.

2nd thought: Spark, check for loose or damaged wires. IE-Spark Plug, Key Switch, On-Off on the handle bars, wires going to the engine. A while back I install some lights on my front rack and spliced them into the front head light on my scram. After removing them and the rack, I taped up the connection. Only a few rides later it would run fine then sometimes it would cut out and backfire - sometimes even die. I traced it those connections, I used liqud tape to fix the problems.

Check and see if any wires are touching or rubbing, it can and does happen.

Good Luck and let us know.

 

the atv has less than 300 miles on it and we have put it back completly stock twice and it runs excellent.we have run 25 /30 and 35 pilot jet and run between 250 and 300 on the main jets with no difference.also we have moved the needle all over hell and it still has this miss.we have talked to everyone //hot seat //ritter// hpd//know one has seen this before.is there a chance its the pipe bad??

 

I had the stumbling problem and what I had to do to fix it was to move the clip on the needle of the carb up or down I can't remember which it was but one way will make it much worse and the other way will fix your problem. I have pretty much the same setup except that I have a bigger carb and it is bored .040 with wiseco piston and rings. It is an easy fix though.

Balzak
2000 scrambler 2x4
I am guessing but it has to be around 50 horsies

 

I have an Explorer that was doing the same thing after I put my pipe on. I have to adjust the choke at the carb. This fixed it for me.

 

if you try to run it hard off of the line when it is still cold it will run perfect but when it warms up it is a dog out of the hole again.could it be the choke?it also has the stock air inlet set up.

 

real4x4~
Running great while it's cold tells me it likes the lean side. Engine warms up and it's a dog again = rich. So I would say your running into a Rich Issue. And yes, this could be caused by a choke. You could also pull off your air box cover and this will be like moving your needle up one or moving your Main down one. Good Luck on resolving this.