i bought cbr yesterday. do u know whats the problem? that sound isnt normal? help plzz

 

Its not running on all cylinders

Edit:
If you let it warm up, spray a mist of water on each cylinder's header. The ones that are running will immediately evaporate. The one(s) that is misfiring will not evaporate the water, it'll linger.

Then you know what cylinder you need to check. Plug, plug wire, coil, carb.

Was the bike sitting?

 

2 left cylinders is out of game. it wasnt sitting. it went broken after riding!
thanks for ur answer!

 

It's only running on 3 cylinders. First determine which exhaust pipe is cold. Run the bike for a bit (20 seconds) and quickly touch the pipe. 3 should be warm and one cold. Or let it run longer and spray water on them, hot ones will steam. Or use a IR thermometer if you have one. They are wicked cool.

Then check to make sure the plug wires is fully seated and make sure it's not worn through or cracked. Then try pulling the plug and see how it looks. It could also be something wrong with that one carb too. If the bike sat for a while, it might be worth cleaning them. If you don't find anything after this, then run a compression test and make sure the motor doesn't have a dead cylinder.

 

Are you saying you have 2 cylinders on the left that aren't working?
Or are you saying that the #2 cylinder isn't working?

 

As others said, check and replace spark plugs, open and clean carbs, pretty much the two things that can cause that are a bad plug or crap in the carburettor.

Missäspäin muuten vaikutat? onko alkuperäinen ilmanputsarikotelo paikallaan vai onko korvattu jollain podifilttereillä?

 

If it has not been sitting and has been ridden regularly, I'd start with the ignition.