Got it not running ordered after market carb got it running but hard to start. Old carb that came on it was junk where it hooked to air box chunk of metal was broke out of end. So friend gave me a carb off of a 2000 500 sportsman that needed rebuilt. So ordered rebuild kit and rebuilt, Now it starts a lot easier but cuts out about mid throttle idles fine when at idle it will rev up good but when riding it cuts out

 

Carb jetting was close on both machines. 157.5 main jet on the Magnum,155 on the Sportsman. Is the air box and filter in place,if not that can be the problem. Plus pull the line from the carb and crank the engine over. Should be a steady or pulsing flow from the fuel pump.If these check out you may have to retrace your steps on the carb. Easy to get the small plastic parts holding the needle in place in the carb wrong also as some have done. I Know you've posted before but can't remember if you checked the exhaust lobe on the cam also for wear or scoring.

 

Air box and filter in place. Cam looked good. I will recheck the carb.

 

Make sure all passages are blown out and you can see daylight through the jets. Also if you didn't thoroughly clean the needle jet when cleaning the carb,it can cause problems as it has a lot of small holes that need to be open.Item #6. Look at the slide needle and plastic spacers also to see if they are installed correctly.

 

Adjusted fuel -air screw out. Starts a lot better cold now it is backfiring thru the exhaust and is hard to start when hot. When cold u can ride and runs great but when it warms up and you let off of throttle it back fires

 

Normal pilot screw setting is 2- 2.5 turns out,some a little more.Make sure you have the throttle adjusted to where s;acl is no more than 1/8" on the lever. If you have a more than that the ect points in the throttle housing can bounce and cause backfiring also.Too much slack and the machine will die or won't crank unless you hold the throttle open. Plus not a bad idea on checking valve clearance(.006 intake and exhaust) Valve clearances drop when hot and if too tight to begin with this can cause backfiring and hard starting when hot.

 

Don't know the complete history of this machine looked at cam last year and being a rookie it looked good to me. That being said I think I will order a new cam and exhaust rocker and try that.

 

This can help on mechanical and electrical problems along with fuel and carb problems before you spend big bucks.https://www.tradebit.com/filedetail....pair-1999-2000

 

Ok I'm back . finally got around to working on this bike again. Ordered new cam and exhaust and intake rockers and installed yesterday and man I will tell you this. It is so nice to go hop on this machine hit the button 1 time and it fires right up and purrs like a kitten the exhaust side was worn down to a sharp edge thank you to OPT for your input on all post that you help with NOW TO RIDE

 

Kinda hard to see exhaust lobe damage when installed but if you turn the engine over slow enough you can see the worn lobe and usually scoring marks on the lobe. Glad it's fixed and running right. I found plenty worn down just like the one another member posted a pic of.http://forums.atvconnection.com/pola...d-cam-pic.html