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Popping CRF450r 2008

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Hey All,

I have never posted but I have used thumper talk to get my bike squared away, very nice info and details. I just wanted to update some people that may have a honda crf450R carburated. I went thru all the forums for an after fire on a CRF450r and went thru them all with no luck. What fixed it I never found on the forum so I wanted to start a thread incase others were having similar issues. 


So what happened was my bike started popping like crazy nothing had changed (jetting, fuel screw, etc) checked for air leaks none, rebuilt carburator nothing, adjusted fuel screws thru all extremes in 1/8 turn increments nothing. Thinking it was jetting I rejeted to a ridiculous level sea level -28 degrees popping went away but had a bog. I finally realized the only thing I had not checked was the Float Level. After checked electrical, carb rebuilds, air leaks, etc I decided to check the float, did not think it would have a impact but by sure it did. I made a U out of cardboard |____________| 8mm deep and the width of the carb (saw this on thumper it worked wonders) and checked the float, I soon found out it was out of wack by 2mm (needs 8mm) I checked this by running fuel thru until it shut off and measured. Once I got the float figured out and measurement right I re-jetted to my altitude approx 50000 ft. with temps from 40-100 degrees (did a 172 jet, 42 slow jet, 2nd clip on the needle and my problem went away with a couple turns of the fuel screw no popping on acceleration (slight pop on decel when you go from full throttle to no throttle I believe this is normal or semi normal). 


I never saw the float mentioned so I do not know if the 3rd time taking apart the carb is the charm or if adjusting the float had that big of an impact. So if you CRF honda is popping while accelerating and you feel like your carb is clean and not plugged check the float it may save you some headache. 


Thanks Thumper Talk, best forum for any info on almost anything. Amazing experience here, keep up the good work.

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