After letting off the throttle the engine backfires and ocassionally stalls. The Ozarkis new and has not been back to the dealer since new, about 30 hours. I know it was suppossed to go back after 10 hours but my wife bought if while I was deployed and I just returned. Is there a simple adjustment I can do or should it go back to the dealer and if so what can I expect for a service fee. I already changed the spark plug, cleaned and oiled the air filter and changed the oil. Thanks

 

if you want to do your own maintinance, buy a service manual. (best investment you can make in your ATV, IMO) i would suggest a valve adjustmant first off. and it sounds like you are running too lean. find the pilot jet on the carb, small brass skrew outside the carb bowl. bottom of the carb twords the engine. if its a mikuni carb, pretty sure it is, then turn that skrew IN 1/4 turn at a time until it no longer backfires on decelleration.

welcome to the forum! dealer service fee is about $60.00 to look at your mechine for an hour... if they dont know whats wrong more $$$

 

First of all, how long has that gas been in there? I'm asking because you said that you were deployed and I didn't know how long the Ozark had gone without being ridden. Sometimes old bad gas can cause symptoms like you describe. It's cheap and easy to dump the old gas if it's been in there more than 3 or 4 months and replace it with fresh gas.

Improperly adjusted valves can cause the same symptoms but I doubt that your valves would be that far off after only 30 hours of riding. We've had our Ozarks for 4 years with hundreds of hours of riding on them and we've never adjusted the valves because we've never had similar symptoms like you describe with our Ozarks.

We have, however, seen the same symptoms with a dirt bike that I had once and replacing the old nasty gas in there fixed the problem.

 

you would be surprised how off the valve clerances can be on "new" mechines... iv seen them nearly 1/4 inch off spec! its worh doing if nothing else cures your problem

 

I would like to hear what the problem was when you get it fixed. I had the same symptoms with my 03 Ozark. My first thought was to clean the carburator. So I took the carb off of my bike and dropped it. I broke my carb in half while trying to clean it!!!!! STupid me.
So I have a new one coming UPS. Should be here anyday. It was an expensive ooops.
But if the new carb doesnt help, I would love to hear what fixed your problem.

 

I plan on adjusting the valves this weekend, the fuel and spark plug are fresh so if the valves don't cure the back firing then I'll adjust the carb. I'll post what I find out.

 

I'd wait on the valve adjustment. My honda has ran for years w/no adjustment. No reason yours is that far off.
Clean the carb first. Backfiring is usually a lean condition. Then mess with the air screw a lil if it still does it. After sitting, a carb cleaning is almost mandatory.
What color is the plug? Could the choke be sticking?
After exhausting all the carb and electric possibilities, maybe then check the valves.