I am losing my mind over this, jetting the predator, so here it goes..........the only add ons are a k&N drop-in panel filter using the stock box,snorkel,and lid no uni vent holes also a wb pure polaris slip-on & stock headpipe what Im not understanding is according to everyone that I have spoke with if it is running to lean the plug will be white if it is running to rich the plug will be black I am at sea level 0-6000 ft the temps around here have been going from the 20s to the 40s the first run was with the stock jet which is a 150 main I pulled the plug and it reads a brownish color which would be telling me that it should be good, the second run I tried a 157.5 main jet with all 8 discs and the quiet core and now the plug says it would be running to lean what is the freakin deal. Im just afraid of blowing up the motor now if you lived at sea level and had the same add-ons as me what would you do for the jetting and how would you set the wb-slip-on up how many discs would you run and would you run the quiet core with it? the thing that doesnt make sense is I went up in the jet size to give more fuel and its reading lean any help on my matter would be greatly appreciated...........................thanks

 

please I need some assistance in this matter anyone with some knowledge......................

 

i would try a 160 or a 162.5
i am think the 160 will do it tho..

 

I can only speak about my friends Predator up here at 5300ft. altitude. He had the W/B slip on and K&N filter and used the stock jetting. It worked good and we noticed no problems. We added the Hard Rock Racing air box mod and had started with a 172.5 jet. Well, being the ****-lyzer I am I noticed it was crapping out at the higher rpms in 4th and 5th. We felt it was a lean condition so we started jetting it up. We tried 175, 177.5, 180, 185, 190 and each time it got worst and ran like s@#t. Even though we checked the plugs everytime and it started white and went to a light to medium brown. Well, the color of the plug got better but the bike didn't run well. Now to do this as accurately as possible you must run your quad hard all the way into 4th or 5th gear then immediately shut off the bike and check the plug. We did this but the results did equal what we saw. So we started to jet down all the way to a 165 and boy did it wake up and loss the cutout at high rpms.

Now we didn't just feel how it ran, we tested against his wife's stock Predator as a guideline on a paved road at about 1/4 mile long. We wanted to be in the top gear at it's max and see what gains in quadlengths we were achieving.

So since you are at or near sea level, I would go up to maybe 165 or a little less. The best way is to test it several times against someone to see if you going the right direction. That's really a real world way of testing. You may just invest in jets from 160 all the way up to 195 because you may keep modifying your bike. Hope that helps.