I've been riding my new Raptor about 2 weeks now. I've noticed that there is a small flat spot in the low rpm's and if I don't rev through it, it will cough and die. As long as I keep the rpm's up, it seems ok. But even there a few times wile riding it's coughed. Does my Rapor have a bad cold? What would cause this?

 

Turn your idle speed up a bit, Raptors come from the factory with the idle speed set too low. A few hundred more RPM at idle really helps low end throttle response and starting. If it's not idle speed, then check your floats. A bog at low RPM can be caused by the fuel in the carb bowl being too high and partially flooding the idle circuit in the carb. From the factory, Raptor floats are often set a touch too high which causes a low end bog, especially up hill or riding a wheelie. If neither of those fix your problem, you may need to adjust the A/F screws on the bottom of each carb. Somewhere around 2.5 turns out on each to start and then blip the throttle at idle. If RPMs return to idle quickly, you're good. If RPMs drop below idle and then return to idle after you blip the throttle, your AF mixture is rich and you need to turn the right carb's AF screw in a 1/4 turn and try again. If RPMs stay a bit above idle and then return to idle after you blip the throttle, your AF mixture is lean and you need to back the right carb's AF screw out a 1/4 turn and try again.

Have fun with your new Raptor and report back on your tuning progress.

 

OK, thanks for the info. I'll check those things out and report the results.