I just rebuilt my 93 4x4. It has tons of low-end pull which is how I built it. The only problem I have is if I nail the throttle it will bog and almost die and sometimes does. If I roll the throttle on no problems it runs good. I am wondering if it is getting too much air or too much fuel when I nail it. On cars I have usually seen this happen when it gets too much air all at once. If it's too much air I can raise the needle or too much fuel I can lower it. Here are the current settings. 160 main, a 30 pilot, needle at second notch from the top, air screw 1 turn out. It has the head milled, reed spacer, carbon reeds and a K&N. I am at about 6000 ft and ride all the way up to 12,500. What are your suggestions.

Also has anyone ever tried to change the counter balance oil in one of these. I can not find the hole to refill the oil if I drain it. According to the service manual picture there should be a dipstick on the right side back part of the case. Right where it is supposed to be there is a hole but it looks like there is a freeze plug in it. I really want to change it but I don't want to drain it out untill I know where to add more in.

 

I would screw the air screw in 1/4 of a turn and try each time. If it get better as you go in but not good enough you may need a larger polit jet. If you screw it out it gets better but not enough try a smaller polit jet. I went larger on my Bored carb. Read the plug and go from there on jetting. Moving the clip on the needle changes your mid cruzing. Hope this helps.

 

make sure your float level is right and check for anything blocking the main jet.your pilot jet is for idle to about 1/4 throttle after that the main takes over

 

Look on the front of the engine you wil find a plug at about the same level as the blank hole in the back. The dipstick came out in 94 I think and they broke alot till they have now got a metal one versus the plastic. I have dug several broken ones out. If you have a 350 I am fairly sure they never had a dipstick at the rear but you checked it the plug in front. They hold about 70cc or to the bottom of the threads with motor oil.
One more thought, the first 400s sometimes had a lean bog because the carb vibrates so much at lower speeds and it would aereate the fuel in the bowl enough to lean out the pilot than as soon as it got on the main jet it goes. I did see it happen on a 350 once and it was real bad like you described. The 400 cure was to install a rubber dampner under the carb attached to the transmission. But the dampner wont fit on the trans that the 350 was mated with. So a larger pilot or a carb stabilizer of some sort might help. In my case the guy did not care about the bog so i did not pursue it much further. But all Polaris engines I believe suffer from excess vibration because they are separate from the trans which on other bikes they are one unit and it stablizes the engine. The worst thing I see with it is that you have some excessive carb wear especially if you do alot of slow speed riding. More than I intended to type but just my impressions from over the years.

 

Thanks Charlie,

That was the info I needed on the oil issue. Thanks to everyone else as well. The low-end was great it was when I gave it full throttle that it bogged. I played with it a little and it is running great now.