Hi Guys

As planned took my car to the Regular that mechanic and he has identified that carburetor throttle shaft and doors were having a problem that it doesn't idle on low rpm, then we sorted out that by putting my b210 throttle part and then car is idling low rpm and run fine and meanwhile we did these basic things

Pasted Valve seat and refaced the head and install a new gasket kit
Changed all 4 Spark plugs and wires
Changed the Ignition coil
changed engine oil and filter and changed gearbox and differential oil.
Replaced the Brake washers including master pump and new set of brake pads.
changed the accelerator cable with a new one
car is running perfect no miss no noise except alternator noise and pulls better.
but i took it to the emission test that i failed it twice
First Result was

Speed(rpm)=1100
HC(ppm v/v)=857 idle,445(2500rpm) (standard required 1200)
CO(%(v/v)=8.73 idle,7.6(2500 rpm)(standard was 4.5)
Lambda = 0.87
O2=3.94
CO2=2.72

They wanted to reduce fuel mixture so changed the carburetor jet from 75 to 65 size
and then again took it

Speed(rpm)=1100
HC(ppm v/v)=1974 idle,1290(2500rpm) (standard required 1200)
CO(%(v/v)=0.26 idle,0.25(2500 rpm)(standard was 4.5)
Lambda = 1.46
O2=10.3
CO2=7.97

this time we gained CO(%(v/v) but lost HC(ppm v/v) and failed any body can suggest what more to be done where is it wrong usually mechanic is a renown person for these cars but still he is unable to guess it what causes this situation.
I had my b210 done few times earlier without changing a spark plug even but i have never failed so any suggestion guys ? i am little pissed out with this situation now

thanks
regards
sumith