Tune up?

My bike is an 09 Beta 450 RR. Everything is stock in the engine department. It has always popped a bit on decel, but it seems to be getting louder, expecially if I chop the throttle at high rpm on the road. The other issue is sometimes when I go from idle to WOT too quickly it stalls. The popping seems like a sign of it being lean, but the stalling seems like it's rich. Do I need to clean the carb or change my jetting? If it helps I ride at sea level to 2500 feet, temp usually around 10-25 celsius.


Don't have all the answers, but cleaning carb always helps and replace pilot jet if you never have.

Also read about replacing the washers behind the exhaust with new ones and tighten down to help on the popping.

FCR? (new to betas, but had one working perfectly on my highly modded drz for years)

Gentle popping on decel is a sign of slightly rich mix, and is generally considered good. 

Stalling when you crank open the throttle is not good, but if it happens when you're cranking the throttle in neutral at a stop, isn't much too worry about.  It could mean your leak jet and accel pump are not quite right: too much fuel flooding it (not likely), or too little fuel/too much air leaning it out and starving it.  Check to make sure the accel pump mechanism/diaphram isn't dirty or otherwise preventing it from pumping properly.

Generally popping on decel is a lean condition if stock due to your govt./ emissions. An easy way to check if it's a lean bog when hitting the throttle or popping on decel is to use the choke. I'm not saying just turn it on full, just  feather it.

I never touch the choke, when starting It I give the throttle two twists and fires up cold.

Things I'd recommend:

Time the squirt -should be a cpl of seconds (not sure of the exact time, but go with whatever is right for bikes of similar size: ktm/wr/crf) with a full twist held open, and be sure the stream is not hitting the throttle slide.

Clean the accel pump plunger/diaphram: pull the diaphram ass'y apart-there is a direct path for dirt and water into the bottom of it, which will prevent the pump from pumping. 

Make sure the jets in the throat of the carb are clean and not masked by the rubber boot.

For what it's worth, my bike was popping on decel from when I got it new a year ago.

It didn't affect the performance at all, I some ktm guys I ride with and they said that's normal on that engine.

Have read on ktmtalk yo replace the exhaust gaskets and mabye some thin copper washers and tighten the bolts really tight .

Another guy said the only real fix so far was to get the inside of the pipe ceramic coated where it mates to the cylinder.

Is you bike running bad?

Can't figure edit using me phone, but meant is it still running crappy after you cleaned the carb?

Also read the needle wears enough on these cards, so replacing with ocemp or sudco needle may be needed.

It's still running good enough to ride. I'll go through the carb when the weather finally goes for shit. Still nice and warm here and I'm jobless for now. Wife gets sick of me sitting at home and keeps making me go out for a rip. It actually runs pretty good. I'm guessing it's the accelerator pump too rich, or not atomizing as well as it could.

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