RM 250 wont rev out! help!

Hi i have a 2001 Rm 250 that i bought at the beginning of the summer. When i got the bike i knew it needed some work it has about 130psi of compression and usualy starts within 2 or 3 kicks. Now the problem i was having was the bike would start right up and idle fine but as soon as you turned the throttle more then a quarter of the way it would bog out and die, so i took it to the shop and the carb ended up needing to be rebuilt. Now it has plenty of low end power but once you go to rev it out it sputters like a bastard and realy kinda falls on its face. i was running 40:1 now im running the factory reccommend 32:1 with spectro and a  NGK BR8EG  plug. i tried changing the plug and putting the same one in and that didt help, then i tried a BR9ES plug out of a kx 100 and it made a little bit of a difference but not enough to solve the problem. I know these bikes are notorious for bad CDI's so could that be the culprit? or could the bike just need a new top end? or both? Please help!!!

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Does this happen in neutral or in any certain gear. My sons 06 RM85 done the same thing but only in 1st gear at 3/4-full throttle. After pulling down the top end I found it was a gummed up exhaust valve due to previous owner let the drain hoses clog. Try having a look at that and opening your exhaust valve covers and giving that a good clean. Hope that helps you.

If that does not work, sounds like you may be rich on the main jet.  So shop rebuilt carb?  Funny thing I have never had to rebuild a carb (30 plus bikes).  Usually just a good cleaning, with compressed air blown in the passages is sufficent.  Taking a carb off is pretty easy and all the internals are plug and play.

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