Muffler Backfire

[9mmPreacher]

Anyway to prevent this from happening? Every time I take a ride when I cut off the engine my muffler backfires and I am not sure what I am doing wrong for this to happen, any suggestions? Yes I am a noob.
Thanks,
Preacher

[Easy Rider]

Originally Posted by 9mmPreacher

Anyway to prevent this from happening? Every time I take a ride when I cut off the engine my muffler backfires and I am not sure what I am doing wrong for this to happen, any suggestions? Yes I am a noob.

YOU aren't doing anything wrong. This is NOT a common complaint with a GZ250 (assume that's the bike you are talking about). Could be an exhaust leak or dirty carb.

Any known modifications to the bike?

If you are mechanically inclined we can talk further; if not, try some carb cleaner and if that doesn't help, it's off to the shop.
I suspect the repair will be relatively easy and cheap.

[jonathan180iq]

There is a mixture problem somewhere and you are getting unburned gas fumes exploding in the exhaust.

It's actually called afterfire, but how cares?

Along with what Easy said, make sure that you air filter isn't clogged with a leaf or something.

[9mmPreacher]

There are no mods to the bike that I know of, I am also not very mechanically inclined but I am very willing to learn if it's something I could figure out.

If I got carb cleaner how would I use it? Teach me, I am ready to learn.

[jonathan180iq]

Pour-in carb cleaner just gets dumped into your tank and you ride the tank out and hopefully the stuff that you bought will clean out the problem.

Actually taking off the carb and cleaning it is a little more involved. Let's do the easy stuff first and then move up in difficulty if it need to be done.

Did you buy your bike used? If so, go ahead and take off the air filter side cover and remove the air filter and shake it off and make sure it's not nasty.
That and a good quality pour-in cleaner, as Easy suggested, is a good place to start.

How many miles on the bike? Maybe it's time for a valve adjustment. Not something you'll be doing yourself yet.

[Easy Rider]

Originally Posted by jonathan180iq

That and a good quality pour-in cleaner, as Easy suggested, is a good place to start.

Go to an auto parts store. Ask for carb cleaner. This does NOT mean injector cleaner or multi-purpose cleaner. Original Gumout or Berrymans B12 are good. Follow the instructions on the can for how many ounces per gallon to use. Your tank holds ~3 gal.

Do not overlook, however, the other likely causes.

You need to inspect the air filter for dirt and proper installation (not loose or cocked).
Also the air box that the filter mounts into. The connection going back to the carb must be tight; no air leaks.....and that includes the drain tube. The plug for the end of that must be in place.
Also the exhaust pipes, where connected to the engine, mostly, but there shouldn't be any leaks.

[davidc83]

Couldnt this be caused by over-rich mixture? Arent there screws on the carb to lean it out some?

[Easy Rider]

Originally Posted by davidc83

Couldnt this be caused by over-rich mixture? Arent there screws on the carb to lean it out some?

Possible. Thus: "Check the air filter"..... but kind of unlikely since the general nature is to be lean.

What you suggest is generally bad advice.
You need to find the cause of the problem, not tweak the adjustment.
Anyway, the only adjustment available externally is the idle mixture screw and it's probably not the mixture AT IDLE that is the problem.

Need other evidence to help find the cause. Condition of plugs, general running condition, test with a CO meter, etc.