atv idles when give throttle it backfires

chipoffblock · #1 (**permalink**) 03-30-2010, 09:37 PM

My sportsman 400 starts and idles good but bogs and backfires when i give it throttle. started doing it suddenly last fall as i was using it. tried carb cleaner and didn't seem to help so just parked it overwinter and now started fine again but same problem. any ideas?

**blueline15** · #2 (**permalink**) 03-31-2010, 04:39 AM

the carb probably needs a good ole' fashion tear down and clean

chipoffblock · #3 (**permalink**) 03-31-2010, 05:13 AM

Does that make sense that it would start / idle / run at 15 mph nice?

armycopter · #4 (**permalink**) 03-31-2010, 09:38 AM

The pilot jet allows your bike to idle and provides fuel up to 1/4 throttle. That's probably fine but maybe your main jet is clogged.

curtiscapk · #5 (**permalink**) 03-31-2010, 10:11 AM

My Daughters Bayou did the same thing when we bought it. I tore down the carb and used speaker wire strands to clean all the jets out. Put it back together and better but not right. Tore it down again and missed a jet. Now it runs great.

**blueline15** · #6 (**permalink**) 03-31-2010, 02:08 PM

Quote:

Originally Posted by armycopter

The pilot jet allows your bike to idle and provides fuel up to 1/4 throttle. That's probably fine but maybe your main jet is clogged.

agree

Quote:

Originally Posted by curtiscapk

My Daughters Bayou did the same thing when we bought it. I tore down the carb and used speaker wire strands to clean all the jets out. Put it back together and better but not right. Tore it down again and missed a jet. Now it runs great.

agree...

you have mulitple jets for different portions of how wide the throttle is open
....so that easily could be a problem

chipoffblock · #7 (**permalink**) 03-31-2010, 03:25 PM

Thanks for the info. will give that a try before bringing it in and letting them replace camshaft like they talked of. worn cam didn't make sense to me as it started suddenly.

Any tips on how to go about carb teardown???

4getful2 · #8 (**permalink**) 03-31-2010, 04:54 PM

what year is this machine??

chipoffblock · #9 (**permalink**) 03-31-2010, 04:58 PM

not even sure...04? is there a easy way to check?

chicknhwk · #10 (**permalink**) 04-09-2010, 07:53 AM

there is a serial number etched into the frame right behind the left a-arm..should start with a .......4xa...if you get that big long number ..call me @ 1-877-haydens..and i can punch it into polaris' website and let ya know what yr it is....i am a polaris dealer...