04 cr250 bog

im slowly pullin out wats left on my head for hair. i never had a problem with the stock set up pipe/reeds/jetting. but hated power delivery. so i installed fmf sst/ w power core 2, and boyseen dual stage reeds, new topend and new exh pipe o-ring. first few rides was great just wat i was lookin for, a few jets later "390" main and wow!!  plug looks good still a bit dark for normal riding . went racin and all of a sudden boooooooggggggggggg @ wot.  wat the frigg???  i finnished the moto and messed with it as much as poss befor 2nd moto. when i got home pulled carb kleened it and tryed it again. it still acts up a bit, but when it wants to  any sugg???  im thinkin the reeds and yes the restrictor is in the cage.  

What is the standard main jet size? Sounds like it's too lean at WOT.
If you dont have it already, get the JD jetting kit. Trying to fine tune the Mikuni with oem needles is a freakin pain, and time wasted.  
^*^*^*^*^*^*^*^*^*^*^*^*^*^*
Stand in the place where you are, think about direction and wonder why you haven't
North Carolina

The failure mode and or malfunction occured after a few rides of happiness so the problem most likely is a new one.

Start touble shooting by checking each system to narrow down the possibilities. When this kind of thing happens to one of my bikes it sometimes takes a cool head and a second look to nail the problem. I once found a bug nest in the float vent tha caused me to rebuild the carb too many times for now reason.

Best f luck and hope you get it nailed soon.  
bald as a bean..old as your dad..but rides like a fool

my 125 did the same thing it would do it when yor on it to  just like someone was hitting the kill switch on you well i would be like 3-4 th just screaming before this big step up its like 95 foot and i land only like 85 big boys on the 450's land way up there but i would be like braaaaapbraaaaaaaaaaaghblouuuuuuuuuuughghghghguuuubraaaaaaaaaaaaa  etc..

never figured it out and it would do it when i was letting the bike scream i mean 10 laps wide open not *** around either and she never got really hot? always about 215* i wish i had a helmet cam i was running 2:32 on a 1.75 mile track the 250 and 450 were 2:20 theres allot of hills and corners and straight aways getting my bike fixed as she blew up. she just couldn't take it trying to keep up with the 450's on a 125 is f-en hard!! boring to 144 and racing all next year going for 125 c championship. will have a vid of local tracks then  
------
my toys
1998 HONDA CR125 (ported polished,pro circuit pipe silencer graphics seat cover,suspension CMP,boyseen reeds,jetted,southwick tires,polished frame,protaper bars bar pad,renthal grips and donuts,turner vent,IMS foot pegs)boring to 144!!!
1994 YZ80 (SOLD)
1983 srv 40


Im in goon club YES!!

ive checked the carb vent lines ive been told thats a common prob. i try not to over oil the filter and resealed the airbox boot. i did take the stock reed stops off when i installed the dual stage reeds as per instructions.  just finniky i guess. still goes great so no harm no foul.  

Seriously, if you want it to run clean, get the JD kit.  
^*^*^*^*^*^*^*^*^*^*^*^*^*^*
Stand in the place where you are, think about direction and wonder why you haven't
North Carolina