i bought my first bike a few days ago and now it is having issues and i have no idea where to start or what it is. the bike is a 95 cbr f3 600. when i went out to ride today i started it and it started and idled about a min then just died. now when i try to start it it is making a whoosh sound and backfiring out the exhaust. i removed the tank and found out it is also backfiring through the third carb and there was some oil looks like on the velocity stack like it had been spit out of the carb. i pulled the plug on the number 3 cylinder and turned the bike over to check for spark and it started and sorta idled with the plug out and the plug was sparking away but when i put the plug back in it went back to backfiring through the carb and exhaust and makes that whoo sound like gas is igniting in the exhaust pipe. i am at a loss it has ran fine for the past few days started right up everytime. i have not redlined the bike or road it hard just riding it around town. havnt even gotten it over fifty yet. and now it isnt running at all. i am unsure what all has been done to the bike except for a K&N air filter and vance n hines exhaust. it looks like the coils are not stock either. the bolt holes do not line up so there is only one bolt in each coil. i am unsure if it is jetted i do not know how to tell or even where to look. hopefully someone can help me with this. i am pretty mechanicaly inclined so i am hoping to be able to fix this myself i just need to be pointed in the right direction and taught a few things.

 

i have tried tapping the floats. still nothing. the previous owner said something about it was just rebuilt with a muzzy piston and jets but i am unsure of that. the thing is clean enough to eat off of. plugs are clean no discoloration at all. oil is still brown filter is new. air filter is new. does anyone know where a good write up is on cleaning the carbs. i am going to try to get new plugs tomorow i really hope this is something simple. do they make an e3 diamond fire plug for these? whats the best plug . and also can i run royal purple oil and k&n oil filter. if i do a tune up i want quality stuff. that will last and perform cleanly .

 

i feel kinda stupid now. after tearing it down three times and still not finding the problem i was checking vacuum lines after trying to crank it and it not starting and i noticed the fuel pump was hot. i took it off cleanned the contacts made sure i moved freeely and was working and put it back on the bike fired right up. im guessing the thing was not letting barely any fuel through. or something. its the weirdest thing i had ever seen.