450 s starts awesome and runs great when cold but, after it gets warm, just like someone flips a switch, the engine loses power, it will not pull itself in 1st gear, the engine will not rev up hi enough. If the engine dies it will maybe start back up but, it will always just run a little above the starter.If it sits for 1/2 hr ,it will start right up and is fine until it gets warm again. The engine cooling fan works and I had problems w/choke plunger not always going all the way off & installed a heavier spring on it, when carb was off and checked out.Was wondering if anyone had any ideas ? It has approx 2000 miles on it. Thanks

 

check the exhaust my 450es did the same thing about 2months ago found out the baffels in the mufler came apart and pluged the exhaust up...

 

I can blow air through it and it does not seem to rattle any, how did you check yours or find your problem with the ex. Thanks for your help! Bob

 

check the fuel filter. The loss of powr may not be heat related but more of how long or hard the motor is run

 

Since it seems to be temperature related, I'd suspect the coil or other related hardware.

It used to be that you could buy a spray can of freon to trouble shoot heat related electrical problems, but not anymore.

You could try getting it to act up, and spraying the coil down with cold water from a hose. If the problem goes away temporarily, that would be a clue...

 

How long has atv been doing this? has any other work been done?Thanks..

 

Thanks, that is a very good idea! , I might even try to take an aerosol can of key board cleaner with me to try because, it will probably not be close enough to grab a garden hose when it acts up, with my luck.

 

I had put a new one on last year but, will check again and drain out and check tank in case something floats over suction tube. Thanks for the input!

 

I bought the atv aproxx 1 1/2 yrs ago in the late winter, in northern wisconsin, and it started when the weather got warmer and has been getting worse all along. probably purchased someoneelses problem, I did have a problem with the oil light not going out and the fan not engaging but, found the fan controller was bad, replaced it hoping it would fix both but ,here I am.

 

Thanks I guess i would try remove fuel line when its quit and see if fuel is flowing.if not loosen fuel cap and see it starts back flow. if fuel is flowing when you remove fuel cap then fuel system should be fine at this point, I guess next pull plug wire off plug and carry another plug with you and put extra plug in wire and ground against block to see if engine is firing! lets go from there...Thanks get back with us...