B2 low power??

[lasa_dal]

hi !

i have b2 gj74a 40 HP model. the bike was running fine few weeks ago . suddnly when riding felt pikup power is low then before. i whent to highway and check it out.

1. bike couldn't make full throttle at sudden acceleration, it drops on somware 8-10k.
    if i try slowly i can reach 16k
2. bike couldn't go more then 120 kmph at 6th gear

all though its low power , the bike starts fine and idles perfect 

so this is what i did,

1. replaced the plugs
2. replaced  ignition wires
3. cleaned the carbs
4. balanced the carbs


still same issue. i played with the bike whole weekend but no progress.
please give me an advice !!


thanks
  

[pmackie]

Check/Change the air filter before you start doing other major things. Also, how fresh is the fuel in the tank?

[lasa_dal]

thanks for the advice !

air filter already changed

fuel is fresh coz I'm riding the bike everyday

main jet was 90 (was 100% OK before) i changed it to 100 but still same no improvements.

is there a possibility of CDI fault??

[pmackie]

Is the engine firing all 4 cylinders? You can check to see if all exhaust pipes are getting equally hot, and/or check the plugs to make sure all have decent colour.

The next thing I would check is the fuel flow from the tank to the carbs. If you have an in-line fuel filter, either change it or remove it. Check to make sure the petcock flows fuel properly. You should NOT be changing jets if it ran fine before, you need to find out what changed.
 

[lasa_dal]

4 cylinders are firing add fuel flow is ok
 tho o rings on the jet holders are leaking i think . im going to replace them . i will post the results after that