Hello All,
I just recently picked up a 03 juiced up predator. I now need to become a carb jetting expert along with everything else this thing throws at me. This thing rocks but I have some engine popping at WOT that I am working on. I cleaned the carb (which was spotless) changed the plug and cleaned the UNI air filter. If that doesn't help I am planning on trying a 150 main jet. (currently has a 160) And no I will not be riding at WOT but I need it right. Test riding later today. I'm telling you this thing is scary fast but fun.
How can I determine the size and model number of the Mikuni carb on this beast.

 

Unless its a replacement flat slide carb as some have installed,it should be a 42 mm BSR Mikuni.(Measured in mm by the intake bore opening) Kits are available on E-bay instead of going through the dealer piece by piece. Stock main jet for the 03 shows to be a 150 main (depends on altitude and temp)) Best way is to "plug chop" at high speed,just kill the machine at top end and check if the plug is light to medium tan.If whitish,you need to bump the main jet up,plus you may have to play with the slide needle to fine tune it. Popping could be a lean or rich condition.(or if it has an aftermarket pipe they will do this!) Just check the plug! OPT

 

Thanks OPT,
I test rode the quad today and it ran much better with just the clean out. It does have a FMF pipe.
The dirt road was a bit wet so I had to take it easy. It's running better each time out. I did develop a fuel leak at the carb. I ordered a new bowl gasket so hopefully that will cure it. Four day wait...