800 Polaris Engine Failure Prevention

I have an 08 dragon 800. it runs fine all the way up to about 7000 rpm after that it starts to spit and sputter. what could be the problem? Where should I start the search? I have had a new fix kit installed about 250miles ago, and the computer has been updated and reflashed. Help!

May need to adjust or replace your TPS sensor.

at that RPM, i'd be looking at the exhaust valves for carbon buildup or a plugged passageway on them. i've also run into similar problem where my sled wouldn't build RPM, and i found that my primary spring had broken off the last coil and was causing the clutch to bind slightly.

good luck with the sled.

-B

X2 on the exhaust valves needing cleaning.

i purchased a used 2009 iq 800 and was told it had all of the updates - Friday i was about 20 miles into my trip - trail riding and was mildly accelerating thru 4 - 5000 rpms and experience a complete shut off- like someone hit the kill switch. Went to pull it over - engine was locked up solid. After cussing a few minutes, I pulled the plugs- nice brown color. Pulled the motor over a few times with the plugs out - put them back in an she fired right up. Ran it very easy to the next fuel stop (30 miles) - filled her up and a added 2 pints of oil to the gas. Ran great after that although I have never been able to get more than 7900 rpms out of it. Plugs are black with oil now - seems to be hitting on both cylinder, however, i have zero confidence in getting on it.
Then Saturday, chain started slipping - had to tow it back -as i could not adjust chain. Pulled gearbox apart today- no lube with disintegrated chain tensioner- was melted and disfigured.
Can I reuse the chain and sprockets??????
Please advise on any area of your expertise.
Thank you.
I will hang up and listen.
Mark

I can't say I have experienced the engine difficulty as you have to help you out. Maybe just a glitch caused to shut down? Sounds like you need to drop the weights to get full 8000+ rpm or your exhaust valves are on the way out? May experience with a wrecked stuff is use all parts. $300 ish dollars can replace sprockets and chain, depending on what else is hurt

Scuffed both pistons last year 2000 miles, dealer said ejector oring was bad and crank seal were gone, New seals orings, cylinders, pistons by dealer and warranty for 90 days, this year 700 miles later scuffed pto piston, put new one in and drove 40 miles and det and running lean, What next, back to dealer, CV teck, the programming is pitiful, det light at mid range, ready for 4 stroke, sick of piston probs