backfiring on deacceleration on 05 crf250R

sprocket218

Member
Aug 25, 2006
14
0
I hadn't ridden my crf250R for quite awhile (6 months) but I had emptied all the gas from the tank and the carb. I just added a new sprocket with 2 more teeth. I took the bike out this weekend and I had deacceleration popping with a little bit of backfire once in awhile. It had never done that before, can it be the new gearing? Is it because it sat so long? Thanks, Nancy
 

Grensjos

Member
Sep 12, 2007
16
0
did you put brand new gas in or is it from a can from last year. the fuel may not have enough octane! i think you need to run 103 octane min. in your bike
 

Chili

Lifetime Sponsor - Photog Moderator
Apr 9, 2002
8,062
17
sprocket218 said:
can it be the new gearing? Is it because it sat so long? Thanks, Nancy

No it is not the gearing. Was the weather a fair bit cooler than when you normally ride? An occasional decel pop is not a concern if it is excessive then your pilot circuit may be a little lean.

As far as octane you do not need high octane fuel for a stock 250f.
 

sprocket218

Member
Aug 25, 2006
14
0
The gas is new, not from last year. And, yes, it probably was a little cooler than I normally ride but it did it quite a bit. Every time I came into a turn and really slowed down a lot but not any other time. Should I try to turn out the pilot screw a quarter just to see if that helps? I go back and forth from a 2-stroke to a 4-stroke all the time and it gets kind of crazy. Thank you for your help!
 
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