Backfire when decelerating?

[01ps]

I have a 1985 Honda BR 250es. When decelerating in gear I am getting "popping" out the exhaust, and very occaisonally a larger backfire when in gear with no throttle, such as idling down a steep grade. Any common reasons for this? Fixes?

[Erics350x]

adjust your mixture screw

[Rustytinhorn]

Incorrect fuel/air mixture. Sounds like its running a little rich.
You will have to play with your carb and see if you can fine tune it a little.

[ATCwithdrawals]

Also, you might have a slight exhaust leak that will tend to draw in fresh air into the exhaust when decelerating and will cause this problem. Had it happen to mine once.

[01ps]

Also, you might have a slight exhaust leak that will tend to draw in fresh air into the exhaust when decelerating and will cause this problem. Had it happen to mine once.

How far back in the exhaust system would this be a problem? I don't have a factory muffler on it, and I may have a slight leak where it is connected because it is not an OEM size pipe, but I didn't think that would casue a problem if the leak is that far back.?

[01ps]

Incorrect fuel/air mixture. Sounds like its running a little rich.
You will have to play with your carb and see if you can fine tune it a little.

Are there any instructions on doing this anywhere? I can only find base instructions for the pilot screw, but no other instructions in my repair manual or owners manual.

[Daddio]

Also, you might have a slight exhaust leak that will tend to draw in fresh air into the exhaust when decelerating and will cause this problem. Had it happen to mine once.

I would have to agree.

[stoney420]

this should give u a pretty good understanding of carbs..
http://www.3wheelerworldforums.com/showthread.php?t=55086

[Rustytinhorn]

Are there any instructions on doing this anywhere? I can only find base instructions for the pilot screw, but no other instructions in my repair manual or owners manual.


this should give u a pretty good understanding of carbs..
http://www.3wheelerworldforums.com/showthread.php?t=55086

Thanks Stoney.

[01ps]

Also, you might have a slight exhaust leak that will tend to draw in fresh air into the exhaust when decelerating and will cause this problem. Had it happen to mine once.

I did find a leak right at the joint near the kickstart, havn't fixed it yet, but it was a fairly large leak that was not loud (compared to the muffler), so I didn't notice it till I blocked off the muffler.

[ATCwithdrawals]

My freind put a aftermarket on his BR and had a leak in the same spot as yours and after we repaired the leak it never backfired again, so I'm almost positive that when you repair this leak you will stop the backfiring..