Hey guys, I have a 2002 Sportman 700 Twin and i just installed an 800 header and a white brothers (Pure Polaris) exhaust pipe. Upon reading the instructions, it says that i DO NOT need to rejet. For my setup, I took all the defuser plates out and have the exhaust pipe straight through. Do I need to rejet?????? I bought a K&N air filter along with a Jet kit. I do not want to ride the ATV until i know for sure if i should rejet or not! If anyone could shed light onto this, i would greatly apprecaite it!!! THE ATV HAS A VERY SICK GROAN TO IT NOW!!!!!!!!

 

I would ride it a little and check the plug but my guess is you might need to bump up the main jet. You are now flowing more air and will need more gas to have the mixture right.

 

I would definitely go up one main jet size. Ride it arund for maybe 20 minutes make sure you run WOT alot and then check the plug. I take rejetting "suggestions" from the companies and then tune to my quad.

 

Thanks guys, I will be sure to check it out. When i rode it a little right after installing the exhaust, I heard the ATV backfire a bit as i was slowing down. So i def. figured i needed to rejet, but I just wanted to be sure! I will not get back to ride my ATV for about 2 weeks or so, but i will def. let you guys know what i find. Also, what size main jet are you running with your set up SPORTSMAN70003?????? Much appreciated guys!!!!

 

I running a bigger carb and I also have a dyno jet kit the main jet I have in right know is a 165 and I have went all the way to a 185mj. I'm still playing with my jetting.

 

Sport700twin, if you machine is backfiring when you let off the gas you most likley need a larger pilot jet.

 

Jetting to plug color on the twins is pretty sketchy, the twins use a "wasted" spark ignition, which means the plug fires on TDC exhaust stroke also, which in turn greatly confuses the plug coloring.

Even stock, the plugs usually are almost white, try plug color at first, but u usually end up going by feel more than anything, remember....make small adjustments at a time.

Put the defuser plates back in, you'll lose your top end.

As stated above, backfiring on decel would be a bigger pilot, & needle raise.

 

Sorry for not responding back guys. The day after i installed the exhaust, i noticed a Water Pump Seal Leak. Needless to say, the ATV is down getting that fixed. This is the 2nd time in 4 months i've gotten a Water Pump Seal leak. I'm not to happy about it! As soon as i get it back i will be adding back diffuser plates and rejetting. I was told that i need to add back the diffuser plates to give the machine the needed back pressure. I will be playing around with that and i will update with my findings!! Thanks again for all the advice!!!

 

Did you ever have the waterpump housing seal plate update done?
it should be a steel plate replacing the plastic original cover.

Jim

 

jimmypsp700,
Yes i did have that update done. When it happened the first time, i got the new cover and o-ring along with the Water pump seal. I apprecaite your information, but yes i did do that! I hope this time when it comes back from the dealer, it will be the last time i have to deal with a leaky water pump!