YZ 250 problems

[02yamahablaster]

I have a 98 yz 250 with pro circuit exhaust, v-force reeds, crankcase seals all changed. compression is good.jetting is 170 main, clip in the middle, air screw 1 and 3/4 out. running 100LL 40 to 1 with Redline oil. The thing runs great on the top end but low speed say 1/4 throttle it is erratic and boggy.I pulled the reeds out and the ends seem flakey. Would this cause this? or is there something else wrong? Thanks

[02yamahablaster]

Put in V-Force 3 reeds in today and it made no difference. It actually made it worse.

[MX86]

hrm.... clean out your pilot jet

[02yamahablaster]

I took the carb completly apart. Cleaned everthing, blew the jets out with my air compressor. I forgot to mention I get a lot of oil out the tailpipe after just a short amount of time.

[MX86]

you could probably use a repacking in the silencer, clean out the fuel filter on the petcock

[NewportHillClimber]

is it low in time?

[02yamahablaster]

I repacked the silencer, and put a brand new fuel petcock on it. I don't know the hours on it. It usually starts first or second kick.

[MX86]

check the powervalve, it's probably gummed up and not closing

[02yamahablaster]

I did a compression test on it today. Held the kill switch off, held the throttle wide open and the gauge read 210PSI. I did this three times and got the same reading.Acording to my repair manual it should be at 100-120PSI. It also said excessivly high compression is caused by carbon build up on the piston. Would this cause my problem?

[nd4speed]

Turn the air screw out more if you go past say 2.5 turns and the problem gets better than your pilot is too rich.