Yesterday I washed my quad and cleaned the K&N air filter and replaced the spark plug.This morning I went to go out for a ride and it was bogging and sputtering very badlly. It would run fine on the top end, but hitting the throttle from a dead stop and around corners made it bog out. I checked the new spark plug and it was fouled with black soot, I checked the gap on the plug, I drained the floatbowl for possible water and double checked the throttle freeplay and all are fine. While in neutral it revs fine, but under load is when it happens.
Any ideas as to what the problem might be? My next step is to pull the carb out and check for plugged jets or float bowl adjustments

 

did you reoil the k&n filter? maybe too much oil?

 

I can rewash the K&N and re-oil it , but I never use a whole lot of oil, becuase I wash it frequently. I will put the stock filter on and see if it is the filter. Thanks!

 

did changing back help any?

 

Nope!

 

Sounds like it's running too rich. Pull the dome off the top of the carb and lift the "C" clip up one notch on the needle then try it and let us know how it works. I'll bet it's hot and humid where you live....

 

Yeah, we have been getting slammed by monsoon in my area and it got pretty humid lately. It will be a couple of days before I can work on it again but I will take your advice and change the needle setting and see what happens, I love my quad but next one is going to be EFI.

 

No E.F.I.......for me.........At least you can work on yours....... 450 with the carb...............What wound you do if you have trouble with your EFI when you get it?.............Caper.........

 

i dont think you should have to lift the needle as it wouldnt all suddened start running crappy. hows the air intake and vents all clear and not pinched? just my .02

 

These things come jetted so rich from the factory that a change in the weather can affect them. My 500 was doing the same thing a few summers ago when the weather got hot and humid and the needle was the fix. I have since dropped two sizes on the main jet and still drop the needle for summer running....