my friend has a 2001 400 scrambler and he bought the hot seat kit.hot seat performance clutch kit and adjustable pipe with silencer and k+n..we put in the 260 main jet and have the needle clip in the middle position and a 25 pilot jet.when you are just idleing and floor it it has a slight bogg for a bout 20 feet then ripps and will flip if you dont lean up.could it be the pipe causing this?we have took out the shims for topend.when it was stock you could floor it and flip it easy right out of the hole but now you cant.could it be the pipe??if it is the pipe he is going to put it back stock because this aggravates him greatly.the dude at hot seat told him to put his stock muffler back on and try it and we did with no help.what could possibly cause this?how does everyone elses 400 run right out of the hole with the hot seat pipe??

 

My bike did this after adding an RCR kit. The jet with the kit was a little too lean, so I went up one size. This made it too rich, and it caused the same problem you have. I moved the needle clip two positions (one at a time) and it cured the problem.
Take the bike for a ride and do a plug reading to see if it is too rich. Be careful you do not go to lean though.

 

his 400 scrambler came with a 25 pilot jet stock and my 400 explorer came with a 35.i had to lean mine out to a 30.hot seat told him not to change his.i can try to brake torque his and it wont even turn the rear tires over untill full throttle..we held it at a certain rpm where it was missing at while we was trying to get it to brake torque and killed the ignition and checked the plug and it was wet.so thats when i raised the clip up one notch on the needle and tried it again.it ran smoother but still no power.still wouldnt brake torque but the plug was now dry when we checked it.any one have any info on what to do??